If someone is putting up illegal ads, shouldn't you file suit against the advertiser?

Advertising is a commercial activity, so it should be reasonable to follow the money and find the advertiser. If necessary, add more requirements for advertisers to be identified/indetifiable so that suits can be served.

Except for online, fault falls under the business providing the venue/platform. You get shot at a concert/bar/sport game, the venue is at fault. Everyone has a duty of care except for online and because they aren't liable, they don't care. Why is there a special carve out for online companies?