Your "criticism" of PCRE doesn't sound like real criticism, it sounds like a confused and frustrated beginner, which is why you're getting beginner lectures.

PCRE is taking an extremely powerful and completely non-standard DSL out of the context of a parent language to which it is inextricably intertwined and reimplementing it for general-purpose use in other languages.

Between that, and the long history of outwardly-bizarre compatibility problems between different regex engines, even those that are supposed to be compatible, you should not have expected the level of compatibility you did.

PCRE's quality is essentially orthogonal to these issues.