There's some inherent risk in the ad blocker as well, though. If it's an extension, you're trusting that this thing you installed, that can read and modify every website you visit, isn't going to do anything sneaky. Yes, maybe it's open source, but every once in a while something sneaks into open source projects, too. It will get caught, but it could be after the damage is done.
I mean, I use an ad blocker. But I don't think it's unreasonable to value security and not use one.
The benefits massively outweigh the risks when it comes to open source ad blockers (lets be honest, we’re all talking about uBO), but limiting your attack surface is a very widely practiced concept in cubersecurity, and there’s no situation where it is totally without merit.