This is kind of why Linux is a minor OS in the Desktop world.  Everyone just assumes everyone has the knowledge to do this themselves.
It's probably for the guy who doesn't know how to/doesn't care to do the compile themselves.

I'd assume he's just testing it on a few of many distros of linux, but it's anyone's guess

A bit paranoid though? I'd assume he'd have bundled a virus in the Windows Binaries if he had a malicious intent