It would be interesting to understand your original arguments if it was more clear what you based that assumption on (which is by no means universal).
2. one expression might be this https://ioptconsulting.com/online-advertising-is-the-new-dig... if the Bill Hicks expression of it was not to your liking.
3. again, I was not arguing for the correctness of the belief that advertising is a cancer, I just noted that nobody should be surprised at it's existence. Maybe it's like this XKCD https://xkcd.com/1053/ in which case congratulations, I've now given you two links to why people think advertising and marketing are awful awful things.
Again, I do not necessarily see advertising as something that is cancerous, but I am familiar with expressions of the idea so I am not shocked, shocked when I encounter it.
I mean it's common enough that Bill Hicks on the subject is pretty much a meme by this point https://www.youtube.com/watch?v=tHEOGrkhDp0
I'm not saying I necessarily agree, but if someone says advertising is a cancer on society or something like that I would not be like - whoa what particular belief system has led him to conclude this?!? - I would think, huh, they have that set of beliefs regarding advertising and marketing.