So, I started looking up some words in the legal sense, since “a contract that can’t end” seems crazy.
It looks like irrevocable in this context means you can only terminate the license according to the rules agreed upon, not for no reason at any time.
The derogatory bit appears to mean you can’t sue them if you dislike one of the minor edits they made.

I’m not a lawyer though, so I’m going to stop trying to interpret license terms, because if nothing else it’s far from my original point.

I have no idea if the terms are good or bad, or even when the change happened.
What I do know, is that I would expect more attention given to it if it were as bad as it’s being made out to be, and from sources beyond one of their competitors.
I don’t trust people using emotionally manipulative language and weasel words to try to persuade me, even if they’re entirely correct. (If it’s as bad as they say, why not actually get their lawyer to provide an explanation, rather than clarifying that they aren’t lawyers and are only guessing?)