I'm a self-identified $OPERATING_SYSTEM user because I have been using $OPERATING_SYSTEM for 20 years in much the same way, like how it works, have a lot of things set up for it which is not always easily portable (e.g. scripts and programs I wrote), and have a lot of $OPERATING_SYSTEM things hard-wired in to my brain and muscle memory.
Can I spend time and effort changing that? Of course. But why fix something that isn't broken?
Am I tying my identify to $OPERATING_SYSTEM? No. It just works for me, so I'm a $OPERATING_SYSTEM user.
Because this can be a form of brokenness. Someone would be hired for their aptitude and probably not because of something they have already repeated over and over (unless we include factory work). The ability to adapt and create (and be creative) is usually not described as such in SWE work, but a lot of the actual work does include that.
That said, if a job has a match based on OS, it would probably just as much be a good thing to explicitly know that you either will be or won't be a good fit based on what you are used to and what you think you can adapt to. Knowing this about a job or a potential hire saves everyone a lot of time.
I like doing useful things; switching tools merely because a corporate policy says so is not useful (whether there are good or bad reasons for that policy is besides the point here).
Says who? I think (as a devil's advocate) it's very useful that people are interchangeable, and that tools are similar enough to allow people to collaborate.
I also think that if (imaginary percentages used) a 10% reduction in productivity because a worker can't use their most bestest tool ever is worth it if it means I can get 40 of those workers for the same price as 10 workers that are proficient in that very special choice of tool. You can pretty much exchange any of those with management overhead or policy requirements (be it by law or otherwise).
I'm not saying there aren't completely valid reasons for a business to have certain policies limiting the software used by their employees (including OS choice), it's just not useful for me. Learning a new language or technology is useful for me because I can then use that language or technology. But switching OS or editor or whatnot well enough to be my daily driver? I don't really see how that's useful for me. I don't really learn anything new, and I won't be any more productive; it'll just be "a thing I have to do, grumble". That's it's useful for the business is a separate thing.
> tools are similar enough to allow people to collaborate.
I think this reason in particular isn't all that valuable though; especially not since people tend to customize their setups anyway. I once worked somewhere that mandated software choice (including IDE) for this reason and I never saw any value in it.
Can I spend time and effort changing that? Of course. But why fix something that isn't broken?
Am I tying my identify to $OPERATING_SYSTEM? No. It just works for me, so I'm a $OPERATING_SYSTEM user.