Because the thing that centos has morphed into isn't terribly useful. It gets most updates early, and as a result has many bugs, which often take a good while to get fixed.
However for security issues it's the other way around - RH won't release security fixes into centos until they've rolled out across all their sold products, even long-term maintenance releases of old OSes. This can take weeks.
End result: many bugs, often broken, and can be missing security fixes for far longer than any sensible user would be comfortable with. It's a product to make facebook (who are the primary user of it) happy essentially, and very little else.
My source comes from watching the IRC channels every single day, and seeing what users complain about and how long it takes to get fixed, compared to before the switch to stream. And for important security fixes there's a huge change - I've seen upwards of two weeks for kernel vulns in 8-stream that would have been O(hours) previously.
> Practically how is that damaging your use case by using CentOS stream? Do you see many things being unstable?
I don't know what the actual rate of bugs ended up being; I burned CentOS from my infrastructure when the news dropped.
> It doesn't refer CentOS as a beta release of RH.
Yes, RH is quite attached to their lie that the thing that gets changes before the next stable version of their commercial product isn't a beta. It's unclear to me whether they somehow actually believe this (and if so, why they're giving free users a supposedly better product than paying customers), or if not why they expect anyone else to believe them, but that is indeed their official claim.
It wasn't a live or die change but people seemed to have freaked out somehow.