All of these problems started from the early days when this a.hole claimed to be Satoshi and the community paid him a lot of attention. If he were ignored from day one
In the Bitcoin community people did pretty robustly ignore him, but that actually played into his favor. The problem is that ignoring him looks like uncertainty, -- the community didn't make it clear that wright's claims were unequivocally and absurdly false. That left room for people who were stupid or unethical to propagate endorsements, because it wasn't unambiguous that they'd be instantly market as idiots or scammers.
and people like Gavin hadn't legitimized his scams in those days this scammer wouldn't have gained this much foothold that he has now to cause this much trouble.
Absolutely-- Gavin and Jon Matonis have a lot to answer for here, similar but to a lesser degree for Roger Ver, Cypherdoc, and other prominent (former) community members that promoted wright. At least Ver has publicly withdrawn his support, though it took an astonishing amount of time and nagging.
The state of journalism these days is that many outlets will publish extremely sketchy speculation as fact ... so the endorsement by those figureheads has been decisive in the continued treatment of wright's obviously fraudulent claims as credible by the media. And the media's representations have been critical to wright maintaining a collection of victims and conspirators.
The support of wright's fork(s) by exchanges have also gone a long way: they lend legitimacy, they create an avenue for third party downstream scammers to fund themselves by promoting wright, and they directly finance the scam by creating an avenue for the scammers to pump/dump on the news cycles they create.