Isn't finding and pointing out a fundamental flaw in how you want to accomplish X the opposite of pedantic? "You shouldn't be doing this in the first place" is quite often the best answer, even though it's not the one you want to hear.
The problem is when people treat questions as having fundamental flaws when they don't.
We often have to maintain legacy systems running on ancient servers, or with code that doesn't quite fit with a perfect theoretical framework of system design.
99% of the time when someone on SO asks "how do I decrypt a password hash?" the correct answer is "you do not, being able to do so is very bad" because it's a common newbie point of confusion. 1% of the time it's "hashing isn't encryption, you want a form of reversible encryption for this particular use case". At no point is a user going to get a "how to reverse a bcrypt hash" answer.
Every once in a while the questioner gets pissy about both of those correct answers, because they're so focused on the answer they wanted they can't understand the problem.
There is no fundamental flaw in using very old software that still works.