I don't like MSFT as much as anyone else but this does feel like a misattribution of blame.

On Linux, the "default web browser" is part of the XDG specification and available under the settings key `default-web-browser`. In the absence of such a standard at the DE level in Windows, it seems reasonable to me that developers would have to maintain a hardcoded candidate list of web browsers and their likely executable paths in the filesystem. And yes, of course MSFT would put Edge on the top of this search list, the same Apple would do Safari, or Google would do Chrome.