but windows still supports 32 bit executables, I'm pretty sure?

Windows stopped supporting 32-bit Windows (i.e., Windows 11 is 64-bit only). They still fully support 32-bit apps, of which a lot still exist. Visual Studio 2022 is the first version of Microsoft’s flagship IDE that is 64-bit, for example!

yup, which is different from the claim that was made. TFA incidentally also was caused because of 32 bit software running on a 64 bit linux system.

You could probably guess I don't claim to be authoritative here. :D I just recall there was a story not long ago about them doing some hard decisions going into 64 bit. https://learn.microsoft.com/en-us/troubleshoot/windows-serve... seems to indicate that you should mostly expect it to work.

Odds are high I just saw the headlines about how they are stopping 32 bit sales of their OS. Though, I couldn't tell you for sure what I was misremembering.

Apps will still overflow if they try to parse a 64-bit Unix timestamp using a 32-bit integer. If that's the case, I imagine they'll break in interesting ways.