Don't be delusional OP, chances are you didn't get banned for your "exceptional build".
The tribunal takes decision based on the chat log. If they see you're a rager, or simply a bad-mouthed person, they'll punish you.
And yes, ignoring them is a solution. Have you actually tried not answering the people insulting you? They usually stop when they see they get no answer, because it's no fun to talk alone and hit on someone who doesn't care.
PS: you probably didn't get your winning streaks because of an amazing build either. Lulu is just one of the best solo laners at the moment. And if it's that good, you should move up to a decent elo pretty quickly, so you won't get reported for that kind of stuff.