Notice that the question isn't "why is PulseAudio bad", but "why do people think that PulseAudio is bad".
The latter is actually more likely than the former to solicit opinion.
"Why is PA bad?" (while still soliciting opinion—don't get me wrong I would have voted to close this as well) is at least ostensibly focussed on the technology.
Asking why people hold opinions and prejudices is a fool's errand. It is not possible for any of us to see into the minds of those who have well-reasoned and technically-based views about PA, let alone attempt to understand the ratmangle of paranoia and delirium that constitutes the "reasoning" for a very vocal section of the FOSS community about the inherent evil of PA and its creator.
There may be very sound reasons for eschewing PA (I don't know, I don't use it myself1), but as soon as your line of inquiry includes normative terms such as "like" or "dislike" and "think" or... whatever the opposite of that is in this case, then the question—and given the alacrity with which the zealots materialize—and the vast majority of the answers, will be the typical roll call of flamebait, trolling and pointless posturing.
1. By way of clarifying my position regarding the tin-foil hat wearers, I do use, quite happily, systemd and have no fears that Lennart is trying to overrun my machine or the wider *nix ecosystem.