You are partially right. There are ads that are truly useful and those which are malicious, such as popunders which often include scammy pops. I use adblock to prevent the latter. There are popunder ad networks which are trying to fight against adblock by introducing "solutions" like anti-adblock, see here: https://propellerads.com/blog/anti-adblock-3-monetize-99-per...

I side with the adblock solutions in this war.