Is this supposed to be an example of something unreasonable?
Of course a publican can ask anyone to leave their bar for any reason or not reason at all, as long as it's not because of a protected characteristic. I think that's extremely reasonable.
And literally the whole point of this conversation is that Facebook has a monopoly on locally targeted online marketing, they're not stopping you from advertising on Myspace, what's stopping you from advertising on Myspace is that it's pointless.
Sure, technically Facebook doesn't have a 100% perfect, totally clean monopoly with literally no competitors, but that doesn't mean that them owning a significant majority of the targeted local advertising market isn't a monopoly problem and shouldn't therefor be legislated against.
At the very least it would also give pause to all of the media companies whose content has made them so much money, since you’d have to ask which other areas would be meddled with. That doesn’t need to be a legal process to have an impact on their business.