Science

Well, on the one hand, I do believe that dogs and cats have emotions similar, though likely not as complex as humans, and that if you know a cat or dog well enough, you stand a good chance at understanding some of its fairly basic emotional states.

Dogs and cats are both usually quite capable of sensing emotional states in humans, though each one will react a bit differently, so in that regard, they are sort of humanlike.

But... you wouldn't be able to understand a cat or dog's very specific opinions about a topic it could not possibly grasp.

Sure, you can probably tell if it likes or does not like a person or kind of food... but its not going to be capable of having complex opinions about fashion or politics or finances or something.

When people seriously act like their pet is telling them things that are far too complex, this person is either delusional or basically manipulating/guilt-tripping you by presuming to speak for an animal, and then they'll say 'Don't blame me, pet just doesn't agree!'

This is basically the behavior of an immature child or a manipulative sociopath.

Also, on its face, I don't see anything wrong with talking to a pet as a form of trying to work through your own feelings...

... As long as you realize that that is what you are doing. That its not much different than talking to yourself in a mirror or a doll or something, in that regard. In another regard, the pet just views this as you spending quality time with it, and it probably enjoys that.

Sometimes it helps to just sit down and talk through your own feelings, and having a loving animal certainly can help you feel more calm and loved.

But again, if someone gets to the point that they actually think they are having a complex conversation with an animal and it is communicating complex opinions back to them... we're back at either delusional or this all being a kind of sociopathic manipulation technique.

EDIT:

Its wild to me that Autists are often described by their tendency to attribute human like emotional capacities to things that do not have them... but its usually never pointed out that we know they don't actually have them.

If I had to guess, I'd say we do it as a kind of coping mechanism of projecting our own experience of being emotional entities treated as unemotional objects... onto things that actually are unemotional objects.

If you can't even pretend to have emotions for an object playfully, you're likely not going to be able to treat an autistic person with empathy.

Kind of a coping mechanism and a bullshit detector at the same time.