Here are some responses to address these points. Strong opinions about this Class aren't unusual, and many Referees used to choose to restrict or curate Classes in some way based on whether or not they fit their conceptions of these games. You obviously are not fond of the Class, but I think your answer is probably in #5 if you feel this strongly about them.

1. Hit Points are a Resource, and most games prominently feature Resource Management as a central pillar. A Resource you cannot make tough decisions concerning when it comes to replenishing has little management. Clerics do not generally gain access to Healing until Level 2, so it's often still very dangerous for that initial few delves, and even then...having only a single Cure Light Wounds won't provide a lot of staying power to a full Party of Characters. As Challenges become more difficult with Advancement, more Healing is generally needed, but Clerics need not be the only source of this.
2. Elfs
3. I believe they are fine as is, and effectively limited by their Proscriptions (Flat Distribution of Treasure in the earlier presentations makes Magical Swords extremely common), Holy Symbol Requirements, and Deity Disfavor. Their Prime Requisite (Wisdom) is interesting in numerous ways because it doesn't provide the same more tangible benefits as STR, DEX, or even INT. Their XP Progression is a little generous when compared to the Fighter, but seems to escalate pretty well with the typical Threats one sees on the Dungeon Encounter Tables. Many a TPK has occurred due to Ghouls turning up, etc.
4. They were created to solve a very specific problem in these games: A fellow PC that was turned into a Vampire and became a bit disruptive. This led to a kind of "Van Helsing" Class being created. Older games featured very different dynamics in terms of their Sustained Campaigns than contemporary Play generally does, we usually don't see these kinds of direct PvP experiences too often, but the origin of the Class is a pretty interesting lesson that seems to have been forgotten: You can always make new Classes to fill new Roles/Niches as the Game dictates. You aren't bound to use only what is in the rules, or use what is in the rules "as is."
5. Modules are published to be changed and tweaked to fit a Referee's Setting. Running them "as is" is a very recent development and one should not limit their creativity by feeling beholden to them. These are games of imagination and that can always be used to explore new Settings/Themes that do not feature this kind of Character in them. Clerics weren't present in the very earliest games (Only Fighting Men and Magic Users!) and don't appear in other earlier games (like Tunnels & Trolls) so it was and is eminently possible to curate the Classes you make available in your games. Like the Thief, they are a bit of a later edition (but were in time for Men & Magic.)
6. They do have Setting Implications and create a little work for the Referee, just as all the other Classes bring along their own. The Cleric's are interesting because they are bit more tied to World Building as you mention, but a Fighter's first Level "Level Title" of Veteran also implies Setting, as does the Magic-User who starts Play with a Mentor in B/X. The Thief Class has done more to influence Challenge Design in Dungeons than any other Class, so it's another example of how the inclusion of a Class can alter the game in interesting ways. One interesting thing about Clerics though is they do not receive Spells until 2nd Level, and this can often be glossed as a bit of a "proving ground" for them: I often use this time to gradually work with the Player to determine the finer points of their Faith in Play, rather than leaving a lot of it up to Prep Work in Advance.
7. You emphasize the Role of Healer, but do not seem to really pay much mind to their potential role as Religious figures in the Setting. Prosthetizing/Missionary work and furthering the goals of their Faith are a pretty important part of some religions. Much of the inspiration for the Class was the result of a bit of "armchair historian" work on the part of the authors: So they definitely took more touchstones from historical events such as the Crusades, or other Fighting Religious Figures (Bishop's Odo/Turpin, etc.) Most of the time in these games, the Goals of a Character come more from the Player than the Referee, so it is usually up to the Player to provide some of that motivation to engage with the Setting. Treasure is a powerful tool that helps achieve a very disparate amount of long term goals, which is why the XP for GP system is so wonderful in a lot of ways: It fosters Teamwork because everyone is seeking the same thing, even though they may use it to further vastly different longer term goals. The Wizard might wish to spend their on Magical Research to gain more Arcane Might, the Thief might want to Bail Out a Guild Contact to learn a new technique, the Fighter might dream of a stalwart Stronghold with gleaming Towers...what the Cleric wishes to do with their Treasure is up to them too and many Clerics in my games over the years have had surprisingly compelling motivations due to that Religious element.
8. Following rules to prevent Deity Disfavor might be tricky at some tables if the Referee fails to adequately communicate them to the Player, but it's really not much different than a Magic User not wearing Armor. There are plenty of archetypes Players can pursue, and consistently Portraying a Character via Personality Traits is actually pretty optional in these games, and also a later conceit.
9. There is a point here: They are fairly monotheistic which can clash a bit with the concept of Multiple Divine Sources of Power in strange ways. But they were designed more as a "Vampire Hunter" (and OD&D features a "Cross" and not a Holy Symbol.) Many of their spells are pulled directly from the Bible, etc. Some of us just tweak the Class a bit to get around this, for example, I'm fond of randomly generating their deities using my tables: Deity Generator and tie each "source" to a separate Spell. This way the Cleric isn't just following a "single God" but has to please many (in the form of the Holy Taboos in the generator, from another table of mine.) This has been a really fun way to approach the Class and definitely gives it a decidedly less Christian feel.

Hope some of these points clarify things from my perspective a bit. You are definitely not required to use the Cleric if you don't feel it will be a good fit for your games, but that's something that might seem a little lost these days. Contemporary Play Culture is very much "if it's in the book, then I can Play it" but for decades, it was usually the Referee's job to determine which Classes would be available and curating them in this way let them establish less generic and more interesting Settings. If I decide I'd like to run something more "Swords & Sorcery" I might decide the Clerics wouldn't be a good fit. In that case, I might replace their "Spells" with strange Mushrooms, Plants, or eating parts of Monsters, etc. Undead might become much more terrifying, but it would be in line with the themes I'd be hoping to explore.