Most free web sites pay for their upkeep with ads. It has been an unwritten agreement since forever (or at least as long as there have been ads on the web) that if you consume the content, you pay the creator by looking at the ads on their site.
Consuming the content without looking at the ads is like shoplifting because you don’t like the way a store’s checkout counter works and/or the fact that they want money from you at all.
Little bit of column A, little bit of column B. There are sites I appreciate which don’t allow you to pay to disable ads - so I sometimes take a look at one or two.There are others where the ads get annoying, so I stay away, or leave when I’ve had enough of 35 animations slowing down my web browser.
I have yet to see an ad that managed compromise the safety of my computer (knocks on wood). I am aware that this has happened, but I would be really cross with BitDefender if it happened to me.