As far as I can tell, anecdotes, social proof, and familiarity play far more a role in the reputations of almost every language/tool than most engineers seem prepared to admit.
(But don't worry, dear reader -- you're probably the exception!)
PHP gets singled out for a bit of extra abuse (some perhaps justifiably, some not so much), but it's far from the only language whose popular conception is not so much based on thoughtful evaluation.
Yes, it's true that there's a ton of really bad code out there. But that's a measure of it's popularity.
There's also a ton of bad C and Java out there.
And yet, no one dismisses those languages because of that.