There's nothing wrong with paywalls and ads. It's annoying when sites with paywalls are posted to public forums since any number of people are not going to be able to join the discussion, but this isn't the site's fault. I think sometimes people forget that they pay for certain websites when they submit. Plus it turns the forum into an advertisement which is not really the intended use.

Likewise, ads are fine in theory but the implementation is absolutely horrible.

Ads are fine, "ad networks" are (often) evil. Content producers couldself-host ads without tracking and do tgeir own ad sales and no one will block them.

Paywalls are also fine. Content producers choice. It's (un-annotated) links to paywalled content that is annoying.