> Are you sure about that? It seems SLE-12 support s390x not s390. Maybe it's multilib support in a similar manner that I've mentioned about RHEL7?

I work at SUSE. I looked at the internal build system. Debian also still build s390 multilib libraries, i.e. on zelenka.debian.org, I can still install "libc6-s390".

And I still don't understand why you are so keen at keeping people from building Python 3.10 on a certain architecture. You don't gain anything by removing these few lines of codes. But you risk at making someone unhappy who - for whatever reason - builds a 31/32 bit Python 3.10 on an s390x system.