Wrong forum for that kind of sentiment dude. Hacker news is not overflowing with people who value individual autonomy. Most people here see themselves as Correct, and so would much rather you do as they do than make your own decisions.
No, we're not. Read the statement again. If you fuck with the headers, you get a totally different and much higher performance result _on linux_.
The charitable hypothesis someone else raised is that there's a bug in how onedrive handles unknown user agents. Neither you nor I have any idea how much effort that will take to fix. You'd hope not a lot but you should never make assumptions about another man's stack. But if it is low effort to fix, Microsoft could get a small land-slide of partial compatibility with one change, which is good PR even if they don't officially support the platforms. It's definitely worth asking nicely rather than giving up and moping about it.
You don't have to lie. Under these circumstances, I often say to the people reporting it very directly "That's not a supported use-case, but I will make sure the relevant people know anyway".
I then go and let the person who owns that product know. Half the time, they say "that's not a supported usecase and it's a pain to change, so it's not happening". The other half of the time, they shrug and say "Put a ticket in, if I can fix it easily I will, I'll take a look when I have time".
Unsupported doesn't mean "no", it means "we're not going to invest noticeable effort into it, and it's lowest priority". Easy fixes may happen, but results are not guaranteed.