If one indulges in activities of a site that has ads, which can be unislamic, is he considered to be helping the owners of the site in sin? For example, one may make a post or create a thread in a site that displays unislamic ads. Is he sinning by doing that?
If you buy bread from a supermarket that also sells wine, would you be advocating wine? Of course not.
You would only be advocating wine, if you actually buy wine.
These ads you mentioned cost money to make and to be posted everywhere. But they only gain money when you click and interact with them.
Just avoid interacting with these ads, and install an adblocker so that you can forget about them.