Earlier quoted context omitted.
I block ads, analytics and 3rd party fonts. Almost every site works just fine.
I do the same (uBlock Origin) and almost every site works, but there are a still a few I need to whitelist because they do weird stuff, like triggering their own scripts to run from analytics callbacks. Airline and banking websites are a couple of common categories of sites I usually need to whitelist to work properly - that's not really an issue though as they don't usually have 3rd party ads.
It's just lazy design, or possibly malicious, I'm not sure.