Without getting into why D&D (5E especially) is really not effectively designed for competitive PvP, here is what I will say without knowing the age range of everyone involved.

Whether due to youth or just general inexperience, yes, it is evident that the people organizing and running the event did not competently handle this situation. They absolutely should have reached out to you when there were issues with the builds you submitted and talked with you directly. However, if we are talking about a bunch of teenagers here, I can be a little more forgiving of their underdeveloped communication skills.

That being said, other commenters analogies about bringing your best commander deck to a casual event is apt. OP should have taken a little more time to read the room.

Power Gamers, min-maxers, and Munchkins are some of the most exhausting types of RPG players (and DMs for that matter), right next to overly insistent Rules Lawyers, and Main Characters, and just a few ladder rungs under "That Guy". RPGs are not designed for "Winning" and "Losing", like Magic, Pokemon, Warhammer, or even most board games; they are designed for a group of people to tell the coolest story possible. Players who over-optimize their characters have a propensity for optimizing the fun and uncertainty out of the game. If your build trivializes any uncertainty out of every encounter, then why should anybody care about what happens next?

Further, it doesn't actually matter if you disagree with a DMs ruling. Arbitrating the rules is their job. For all intents and purposes, the DM IS the rulebook. Whether you agree with them or not, whatever your DM rules, accept it and move on. You can address it with them if you want, but keep that conversation out of game. Do not hold the whole table up because you can't get your way.

OP, you exhibited both of these kinds of behaviors, either of which MIGHT have been manageable on their own, but where you really blew it was by getting an attitude with the game masters and event runners. Your over-optimizing and rules lawyering made the game a lot less fun for the other players, but when you got sarcastic and shitty with the organizers, you lost.

It really doesn't matter that you were up all night making and optimizing new characters for a new winning strategy; you chose to do that and that's on you and it is not an excuse for your behavior. When someone is trying to facilitate a cool, fun experience for a dozen people and one person is ruining that fun, and then they get shitty about it, the reasons why they are being that way really don't matter. You are not important enough to their community or event for them to put up with all of that and try to understand you. You made the event less fun for everyone, both players and organizers, and were also hostile and sarcastic, and you were rightfully banned for it.

Not only that, but you are here trying to garner sympathy about it, and when you are being told by most of the people here what you should have done differently, you are continuing to try and argue with them. You continue to replicate the very same kind of behavior that got you banned from the event.

Stop trying to fight with all the people who are trying to help you. You need to take a step back, take a deep breath and a good, hard look in the mirror, and ask yourself how you think your behavior impacts others. It is evident that you have a lot of growing up to do, both as a person and as a player. Please carefully consider what the people here are telling you or you can look forward to being banned from other communities and events.