Off the subject of who is and isn't a person, there's a much better reason that someone wouldn't want to hire AIs in this universe:
Have you freakin' seen them? A giant percentage of the robots, AIs, and anthro-PCs we've seen would make terrible employees.
Just off the top of my head, here's all the AI beings I can think of, some of whom I can't recall the names of:
Pintsize
Momo
Winslow (It's been a while since we've seen Winslow, huh?)
May
That Neck-beard, hipster guy
Pintsize's Posse of PCs. (We've seen about a dozen re-skinned versions of him, all in all.)
Sattelite AI (From Hannelore's Dad's ship)
That terrifying spider thing from when Marten bought Pintsize
The Vespa Combat robot with lasers who worked with the Vespavenger
Deathbot 9000, whom Pintsize taunted on message boards
The two robots who worked at the chassis store
Now let's examine their character traits as far as redeeming and negative personality traits go:
Pintsize: Good: Friendly, supportive of Martin. Bad: Misogynistic, creepy, arsonist, sexual offender, vandal, pervert, insensitive, drug addict (Or at least, ROM addict), generally gross, repeatedly damages his own hard drive and chassis by trying to eat food.
Momo: Good: Really nice, helpful, socially adept and gives good advice. Bad: Not much here.
Winslow: Good: Friendly? I haven't read a comic with him in a while, but he always seemed a little bland to me... He definitely did nothing to stop Pintsize most of the time, even on some of his really bad ideas.
May: Good: Assertive, has at least some knowledge of social cues, tries to help. Bad: Convicted felon who tried to steal a fighter jet, aggressive, verbally abusive, vulgar
Neck-Beard Hipster Guy: Good: Um... Bad: Rude, inconsiderate, almost got Pintsize killed as part of a joke...
Pintsize's Friends: (These guys are a little less intense, but all seemed pretty similar to Pintsize. Misogynistic, rude, addicts, vandals.)
Satellite AI: Good: Friendly, very supportive, a really nice guy. Bad: Despite the fact that he should be one of the most competent AIs in the world, he accidentally burned out a ton of his circuits while trying to calculate an impossible math equation. After getting drunk.
Terrifying Spider Thing: (We didn't see much of him, but he didn't seem to pick up on any social cues, or realize that he was freaking the heck out of Martin.)
Vespa Robot and the Deathbot 9000: Yes, they were both designed for battle, but they had practically no value of human life and were almost definitely both murderers. (Or at least attempted murderers.)
The Chassis Store Robots: Once again, friendly, but we didn't see much of them so I can't give much of an opinion.
Toaster Bot: Makes toast FUN!
From this cross section, assuming that it stays consistent throughout most AIs, it seems like a giant chunk of the Anthro-PCs in the world are incompetent, inconsiderate, or generally creepy. I won't take off too many points for Pintsize's friends being creeps because his friends would presumably be similar to him, but even if they aren't taken into account a big chunk of the AI beings in this world would make terrible employees. They might make good friends, (At least some of them,) but they'd make terrible workers.
This is completely unrelated, but has anyone else noticed that Momo seems to be acting like a lot less of a Chibi-Anime girl since she got her new chassis? Her personality should be the same, but she hasn't really done anything remotely anime-ish since she got an upgrade.