On the top of people are OK with unobtrusive advertisements.
Ad blockers also block tracking and all sorts of other things you can't see and won't annoy you immediately. Google Analytics can't even measure you if you have real ad blocking.
Even a non-intrusive ad still takes bandwidth. If you do not have infinite free bandwidth, you should try very hard not to waste even one bit on downloading ads. If you do, you are paying to watch someone's ad! We pay to get rid of ads, not pay to see them!
Even the most trustworthy sites serve up their advertisements via ad networks and don't control their ads in-house and by hand. This means that if you visit even only the safest web sites, and block annoying ads, you are still vulnerable to malware and other security threats. For maximum safety you should block every ad possible. I would even argue you should err on the side of blocking real content because the security threat of failing to block an actual ad.
In all areas of life you should work to block all advertisements you possibly can in all their forms. If people want your time, your eyeballs, or your information, they should be compensating you, and you should be explicitly giving them permission.