It's two different sets of needs that don't mix, while neither of them are wrong. It's like me needing alone-time and quiet vs my roommate being a social butterfly- neither perspective is incorrect, they're just different, and they can clash. In this case, some alterhumans need to feel grounded and positive about their humanity, while others (like you, and oftentimes myself!) do not need that, and even find it detrimental.
Humans are just a kind of animal, and they're not better or worse than any other creature; it's correct to say this. You have to take care of your human body and not treat it poorly; it's correct to say that too. But not everyone needs to hear that, because it's irrelevant to the situation. I think my human face is ugly, and that's not a put-down or fishing for compliments. It's just a fact of my life that I made peace with. I don't see humans as my kindred or find any pleasure in their bodies. This doesn't mean I think of humans as beneath me, or that I want them to feel inferior or disgusting. I just don't care for this appearance, and it sounds like neither do you! Everyone can have preferences, and being forced into a certain shape can make the feelings around those preferences much stronger.
It reminds me of when people say things like "You're still male/female, you need to do this and that, and remember that men/women are still good even if you don't like being gendered as one" to trans people. It's unnecessary, patronizing lecturing to a group of people who don't need or want to hear it. Everyone has the right to vent about their feelings even if they don't always cater to what other people think and prioritize. Your feelings about humanity are yours, and you're allowed to talk about them in your own way on your own page. If you're barging into someone else's virtual space with unprompted tirades against humanity then you open yourself up to disagreement and annoyance, but this isn't that.
There's a thing called toxic positivity and I think this can fall under that category. Constant reminders about humans being good and how cool it is to be one, when you're just trying to talk about your struggles, that shit is annoying. Like someone telling you to just smile and think happy thoughts when you're depressed. There are merits to trying to change your thought patterns and there are merits to reminding yourself that humans aren't evil monsters across the board, but there's a time and place for it.
I encourage you to not shut up, because that isn't helping anyone. Respectability politics are all about silencing the people who need to be heard most in the name of keeping everyone else comfortable. You deserve to talk about your feelings just as much as someone who loves being in a human body does. They're a part of the otherkind experience! I think some folks forget that, because it's looked at in a negative light more often these days; no one wants to look like a misanthropic edgelord, but like... being in pain related to our humanity is a thing, it's a huge thing, for some otherkind it's the first sign that something isn't right. Some otherkind love and appreciate their present-day humanity, and good for them, genuinely. They also deserve to express that. But they have no business policing the way anyone else frames their own relationship to it.
I feel like I'm repeating myself here, but I feel very strongly about it. As both trans and nonhuman the parallel makes it even more significant. I can vent about being in this body for so many reasons, and that's my goddamn prerogative. I can call myself ugly when I'm feeling dysphoric without applying that to others. We can feel like our bodies are a prison without implying that others should feel the same. If someone feels like their perspective isn't seen enough, then they can post about it. They can write entire essays on their feelings, no one is stopping that from happening, and alterhumans in general will be all the better for a wider variety of viewpoints and content.