Yes, they allow certain "non-obtrusive" ads by default. Some people might be fine with this, but it should absolutely be opt-in, and their deal with an ad company is the only reason it's the default.
I miss non obtrusive adds, remember when add blockers weren't a thing and we were all fine with the adds in the sidebar trying to sell us virus laden glittery custom mouse cursors? Instead we have an arms race where the net is essentially unuseable without an add blocker.
I'm guessing you missed the time period where opening the wrong page would give you an infinite loop of un-closeable pop-up windows with background music.
Ads were never really non-obtrusive. If advertisers could force you to listen to their slogan at max volume every time you opened your browser, they would do so without hesitation. If you ever saw an easily avoidable ad in the late 90s-early 00s, it wasn't for lack of trying. They simply hadn't personally figured out more annoying methods yet.
I’m guessing you missed the time period where opening the wrong page would give you an infinite loop of un-closeable pop-up windows with background music.
Now we're graced with its spiritual successor - the full-screen browser tab that looks like an "antivirus" warning designed to freak people out and get them to call the 800 number to grant remote access to "fix" the virus.
What magical era is this? Because the before-adblocker time I remember was a hellscape of pop-over popups, sometimes many of them from opening a single web page.
.... ah, those were the days, of flash player ads that would grind your system to a halt with anti-aliased particle spam, minigames, and perhaps a virus too.
Or the sneaky, stealthy, cpu grinding carpet bomb of the pop-under ads, only visible after you close the browsing window.
It's become even worse since mobile became dominant.
Now the ads are no longer a bit of text or a gif, but full page shit covering the top half of what you want to see and stubbornly staying in place even as you scroll. The bottom half of the screen is a sea of cookie and data consent forms who's only interest is in making you agree out of sheer frustration.
And this is fuelled by bullshit, clickbait driven sites that use 10 paragraphs of useless AI generated padding with ads in between, to resist telling you what you went there to find out.
Google has destroyed the usability of the internet, and if it wasn't them it would have been some other greedy fuckers.
ABP allows "acceptable" ads that are acceptable insofar as they meet certain standards one of which is paying them money effectively renting your eyeballs to advertisers.
Ublock Origin: A powerful and performant ad blocker by its creator
Ublock. After the above dev tried to pass the torch to the loser who now controls this he instantly edited information removing all information about the person who actually created it and fund raise off it to the point where the original dev renamed his fork of his own work Ublock origin after it was taken down on behalf of the scumbag who now runs ublock.
In short there is no reason to use anything but Ublock origin
You can disagree with the whole "acceptable ads" debacle (I did and switched to unlock origin) but ABP is far from a risk to anyone using it. There's just better blockers out there.