It's tough to judge because I'm not familiar with the shortcuts anymore but around the time that CSP swapped to the subscription model (or however it works) Krita devs started implementing a CSP mode that changes the default shortcuts to try and match.
Wait, is that only now? I'm kind of confused, maybe I've been on a beta branch or something, I could of sworn that was part of 5.1?
You're right, I'm looking at the release notes now. But it's a very weird deja vu moment. There are a couple of features listed here that I really thought were already released. I need to check what my upstream is...
As tempting as it would admittedly be to get into an extended argument with someone online over prescriptivism and descriptivism in English grammar, it has nothing to do with Krita, so it's imo better not to engage with these kinds of really off-topic comments. Not that I'm always good at resisting the urge myself ;)