This is largely people who were previously Windows customers but who chose to go another way. Microsoft is doing a lot of shenanigans with their monopoly power, and anti-trust is largely toothless.

I know quite a lot of professionals, who for them the last straw was purchasing the professional edition, and then finding out later after an update that their company lock screens now have ad's posted; and worse, those ads frequently have malware that cause even more headaches for them in a unmanageable way.

The bean counters at MS pushed their biggest supporters over the knifes edge, and alot more people are getting serious about alternatives to MS now.