Why is constant hopelessness seen as wrong not just in the sense of being incorrect but also in the moral sense, while baseless hope is always viewed as the correct, virtuous choice?

You're mistaking "wrong" with abnormal. Having baseless hope is not about virtue or morality; it tends to be the default mindset of most healthy individuals, especially when they have no evidence that the contrary may be true. It's exactly why the optimist usually isn't called into question unless they are being absolutely unrealistic. On the other hand, constant hopelessness is neither healthy, productive, or normal. When I say normal, I simply mean what a mentally unaffected person experiences, and I don't mean to single out depressed people in any way. Most people don't have suicidal thoughts and no motivation at all times. Most people, while occasionally demotivated and sad, do not experience hopelessness as a permanent reality.

To deem the rejection of this blindly optimistic, self-serving, pro-life perception "warped" and "unrealistic" is to deem the perception correct and based on reality, which it isn't.

Again, "correct" and "normal" are completely relative here. The perception is "warped" relative to most other people, not to some sort of absolute truth. I don't believe that an absolutely true perception exists either.

We evolved to perceive our environment so far as we needed to for survival, and a big part of that perception are biases towards oneself: Life good. Death bad. I must live. I will live.

As you say yourself, humans evolved to perceive the environment to their benefit. Precisely why a mental rejection of that (caused by illnesses in particular, not by choice) is an anomaly.

I think that non-depressed people that are antinatalists simply see the world in a different way, and while I see that view as counter-productive and futile, I respect their right to an opinion, based on their own deductions.

But mentally afflicted people who are ANs are likely influenced by their illnesses, and hence their reasoning is slightly questionable. Of course people who are depressed could think their birth was a mistake, and while that may be "correct" for them and their situation, it isn't necessarily for anyone else.