Criticism doesn't become unfounded because things become better. Things become better because of criticism.
(I'm not going to weigh in on whether any of the criticisms have been resolved in PHPs case specifically, as I've been away from PHP long enough to not be able to talk on any problems with the current language)
Part of that is due to the share amount of code out there doing things bad ways that were almost encouraged years ago, and tutorials still out there teaching people to do things the old less good ways.
Of course a lot of it is people who haven't touched the language for many years (such as myself) who are at this point a lot less informed than they think they are!
Another issue is that the new frameworks seem to get the positive news, not the core. The language use to describe PHP related libs/frameworks is different in my experience which makes a perception difference: PHP frameworks are often referred to as "making PHP behave" or "removing the cruft from your workflow" where frameworks for other platforms would be described as "helping you make the most of <platform>" and "increasing your efficiency".