There is a spectrum, for people with a certain belief, between 'hypocrisy' and 'principled', which describes how much their actions are in conflict with that belief.

There is a conservation of expected probability thing happening here, so if 'hypocrisy' is more trustworthy than not knowing how someone acts, then 'principled' must be less trustworthy.

But if you said someone was obviously being dishonest because their actions match their words, you'd make no sense.

I am almost completely certain your statement is similarly absurd.

Sure, maybe they're untrustworthy, but we don't need to trust them to believe what they say in this case. We can evaluate what they say independently of their trustworthiness, using logic and experience.

Considering their absolute lack of a real alternative to advertising, this doesn't seem "brutally honest" at all. Simply hypocritical. Using adblockers only works because most people don't use them. If what they are advocating actually caught on (which they know it won't, making them disingenuous) then they would have to shut down their own site.