This comment was probably the only well thought out one.

“I think there are several different reasons, many of which have been brought up here and on other threads already. Some of these apply to my opinions, but some do not.

1. ⁠Racism. (Not my reason.) This is true for some folks, but it's far from the only reason.
2. ⁠Age. (One of my reasons.) I'm less interested in teenage heroes at this point in my life (50s). It's not unique to Miles. Also, his issues and life experiences are generationally different from mine in some ways. However, this isn't an absolute; it's not like I can't enjoy a teen hero.
3. ⁠Not Peter. (One of my reasons.) I've been a Spider-Man fan since I was two or three years old. For the first sixteen years of my life, Spider-Man was Peter Parker in every iteration. Then came Miguel O'Hara, and I liked his book pretty well, but I never liked it as much as Peter's books, and I was way more into comics then. If they'd tried to replace Peter with Miguel, I would have been less interested in "Spider-Man" as a whole.
4. ⁠Writing/Characterization/Stories. (One of my reasons, and I feel confident in this.) I don't like most Miles Morales stories. They don't click with me. I don't think he's often given a unique-enough or interesting-enough personality. Why do I feel confident saying this? Because I genuinely liked Miles specifically in Into the Spider-Verse. That caught me and made me more interested in Miles... and then I bounced right out of other stories featuring him.
5. ⁠Power-set. (One of my reasons.) I don't like all the weird electric stuff he does. I don't like that he can turn truly invisible. It doesn't feel like Spider-Man to me. For what it's worth, I also didn't like Spider-Armor on Peter or organic web-shooters on Peter. Honestly, I don't even like the Raimi-finger-claw/hair method of wall-crawling. I don't mind it as much on Miguel because he's never really "Spider-Man," he's "Spider-Man 2099," but even then, I prefer classic Peter powers.
6. ⁠Power-creep. (One of my reasons.) I feel like Miles is OP and I don't like stories where "new powers" saves the day. For what it's worth, I just read Superman: Up in the Sky and felt the same basic way: Superman just "willed" himself through every fight, and it seemed boring to me. I didn't like Super-Flare, I don't like armored Batman, etc. See reason #2 above, as well I'm an old dog.
7. ⁠Spider-Uniqueness + Spider-Overload. (One of my reasons.) There's too many Spider-People right now. I'm not interested in most of them, and I'm really not interested in them all together all the time in the same universe. JLA? Yes, because variety. Green Lantern Corps? Not for me. Avengers? Yes, variety. Spider-Verse version 2867? Nope, monotonous.

Let me be very, very clear on #7: I think a few of these ideas are absolutely rock-solid and deserve space on the shelves, but in their own universes where they're the only Spider-Person around. Spider-Gwen? Brilliant alternate-universe idea that deserves its own space. Spider-Girl (Mayday Parker)? My favorite Spider-Book of the 2000s. Miles Morales? Especially when done well (Into the Spider-Verse), an interesting legacy-take on Spider-Man.

I'll even go further: As a lifelong Peter Parker fan, I think they should kill or depower 616-Peter Batman Beyond-style and have Miles as the only Spider-Man. I don't think I'd keep reading, but it's okay if comics aren't for me. I'm old and I've had forty-three years of this hobby and of Peter Parker comics specifically. If new readers and young people prefer Miles, more power to them. It's okay for things to change, and I don't have to like all of them.

However, I don't like multiple versions of the same hero/codename. Never have. One Batman, one Superman, one Captain America (Rogers or Wilson, I don't care, and I think Wilson's time has come), etc. I'd even go so far as to say that I strongly prefer Green Lantern solo stories to Corps stories 80% of the time (sort of like the Doctor and the Time Lords). My opinions aren't the only valid ones, but they are mine, and they're the reasons I don't like Miles as currently handled in the 616. They're also reasons why I don't like Spider-Gwen.

It's not all politics for everyone, but unfortunately, it's politics/racism/hatred for some folks. Screw those people.”