First I curse JavaScript developers (sorry). Then I use a heuristic like is this a real website for a real thing that I heard of before today, then temp trust; if it’s click baity or new, don’t trust or try adding in one at a time or mostly just give up. Very little shortage of content.

Depends. Sometimes I leave immediately, other times that blank is just a cover on top of content. And finally, I sometimes have to enable a domain/subdomain using common sense.

It's not that hard, nor time consuming. Again, my wife can do it and she's not a developer.

Still though. There are sites that would not work at all until everything is enabled, including ads. Imagine not being able to buy a plane ticket because wizzair wants to serve you ads