Please read the rules of this category where it says that the people you're addressing don't watch the forum so they're unlikely to see you post. And take a look at the first page, where this related topic is still ongoing.
The thread you linked to is three months old, the admin reply from three months ago says it 'should be resolved' but to 'try again later', and then there's three more months of people commenting that the issue is still persisting.
Why link to a discussion with no updates, no new information, and no solution to the problem?
To OP: I don't know why, but when I'm running a VPN, it seems to open just fine. So maybe try that?
The thing is, this forum is answered by the community, not the staff (no, the moderator is a volunteer, not an Itch staff member).
I understand your frustration, but what the moderator is pointing out is that you're not contacting the staff here, and they're not going to respond. So, there's really not much point in continuing to insist this way. Personally, I don't see a problem with you doing it, but you should keep in mind that the staff isn't going to respond or provide a solution through this channel.
Regarding the problem, from what I've seen (and personally), this issue doesn't affect all users. I haven't had any problems accessing the application, and perhaps that's why the staff hasn't been able to resolve the problem, since they may not have been able to reproduce it. And to answer your next question, no, Itch doesn't have an IT team dedicated to patching the application (please don't ask me why, I don't know; I don't work for Itch either, and I'm simply explaining how Itch works, not defending it).
The application is open source and on GitHub. In theory, anyone who knows how to solve the problem could commit the solution.
Probably because if your like me, your using somebody elses Flatpak install. It might have escaped you, but Itch isn't responsible for that. Hence the lack of a response.
Now, they do have an official Linux installer. (Ask me how I know?), and that too is just as broken (i.e. Cloudflare looping),.
There is a way to fix that apparently, if you can possess minor reading comprehension. The good news is it will fix the problems. The bad news, is it seems to break something inside SteamOS. The App will work as expect, with no CF Errors inside the Desktop, just not inside SteamOS. The App just never starts, it will eventually time out, after 2 minutes, and crash back to the launch screen.
My fix was to install my the Windows version under Proton, apply the same fix, and this works fine under SteamOS, and the Desktop.
Not ideal, but it works. But, it's in line with a my experience with the SteamDeck, for some unexplained reason it seems to hate native Linux Apps, and refuses to run them. Beit Games, or Apps.