While banning or deleting accounts could go all the way from legitimate to oppression, it doesn't seem like banning the account of someone spreading false information that leads to dangerous situations to be an abuse in any way. Yes, we have to hold YouTube to higher standards than others simply because of the disproportionate power the platform has. But this doesn't change the fact that in such cases the measure was warranted.

People constantly misunderstand "freedom of speech" as something that somehow entitles one to trample over someone else's freedom.

For example every time there's a discussion about "hate speech" someone will say that the laws are routinely abused to punish people for their legitimate free opinions. Yet no such examples of routine abuse are ever given. There's room for common sense when judging a situation. Common sense can't be put in law but you also can't really judge these gray areas without it.