

I think the bigger difference is “I don’t believe but I also don’t think others are wrong” is a kind of mentality often. I think that and people are used to seeing self-proclaimed atheists being assholes loudly and go “well I’m not that”. Atheism got fucked over by people who just want to be dicks to religious folks.
Despite it being their software, they don’t maintain this part. It’d be like saying Firefox is responsible for preventing fake bank websites from existing (this is ignoring how they also ship malware protection lists anymore to try and help). The Discover app is just a client where a distro supplies the software lists. On OpenSUSE it browses SUSE (and Flathub, if you add it.)
On Ubuntu it browses Ubuntu’s APT repos and snap.
You can easily alter what repos the software uses too, it’s just using whatever the distribution has configured it to use in conf files and repo lists.