self promotion in and of itself isn't evil, but drive by self promotion in a group you do not regularly participate in is pure spam. we used to allow it on /r/indianfood on the theory that on-topic selfish promotion would be fine, and it nearly killed the subreddit with low effort youtube and blog spam blindly cross posted to a ton of groups.

also I am convinced that while the majority of people don't block ads, pretty much no one values them or wouldn't make them magically disappear if they could.