It's true that all of the platforms you listed have dealt with scams over the years. It's part of the maturation process of any social network. In the case of TikTok, it officially just celebrated its 2nd year as a platform, and I just began to observe a slew of ads on the platform pushing scams unabated. Scammers follow the trends and where the users are, so an extremely popular app like TikTok became a platform ripe for the picking.