I mean, I believe that it's possible you're correct. But this is just such a foreign "does not compute" situation to me. Is the thought process something like "Sonarr is often used to download things against copyright law -> that's a no-no -> we don't do no-no's here"? I'm trying to phrase this as positively as I can, so I apologize if it sounds like I'm belittling the mindset or something. It's not like that.
(It's mildly unfair to Microsoft to imply that this could be the reason, since as a company policy Microsoft can't show up and say "Well actually, the reason we didn't hire was because X" – and this seems like it would be an outstandingly bad decision. Old Microsoft may have made decisions like this, but in recent years they've made some pretty impressive reforms.)