Turned down a job because Windows was mandatory - am I crazy?

A little bit. But aren't we all?

depends on what you had todo maintaining SharePoint ... RUN!

Yes.

Well, yes. Especially if that was your only reason for turning it down.

Yes.

No.

There's nothing wrong with having a niche if it feeds you. I know windows and have coded for it bit my platforms are Web android Linux. Have i fixed windows pcs or helped someone with vb script tests? Ofc. But if I'm your windows sys admin expect me to be frazzled all day

Where is this job? I'll take it.

Well yes, since you can get pretty much every Linux tool on Windows, on top of package managers (the default windows one and chocolatey), terminals (ConEmu)