Lawyers don't decline to give legal advice for free just because they want paying, although they do, and fair enough. Law is a highly complex and recondite field, and a solid answer on any but the most trivial question requires nontrivial research to identify with confidence.

Lawyers also have a professional guild to which to answer, and if they say something offhand which turns out to be erroneous in a way that brings someone to grief, their guild will not be pleased with them.

In fairness, I probably wouldn't take the time here either; on the one hand, I block ads anyway and so don't have such problems, and on the other, I tend only to do that when it's to my own direct benefit that the issue be fixed, and broken ads on a site I'll visit once ever don't meet that test - when Postmates screws up their UI and I have to stub out some analytics functions to place an order, they get an email; here, I'd just add the site to my JS blacklist, reload, read, and go on about my day.

Woa you only ever give paid "expert" advice? Do you also not talk to colleagues in other companies on conferences because you think a lawyer would not have that urge either? Or more generally, if you see a bike light forgotten and left on, do you not helpfully turn it off just because you wouldn't be paid when doing so?

It's not for free: it's in exchange for a potentially better experience.

Never share without a fee then? Not quite the world I want to live in...