It also speaks to a fundamentally broken development process. This sort of thing shouldn't make it through wireframe review because it breaks the core tenet of building a competitor: not fucking with your users' expectations. Something as minor as changing what user handle is displayed was probably hand waved away, if it was even considered, yet here in this thread we have a demonstrable case of a user losing trust and confidence in the project simply as a result of this decision. If you want to convince people to use your software instead of what they're already using, you have to be as close to seamless as possible in all areas that aren't a benefit. In a case like this, the transition from the proprietary marketplace to the FOSS marketplace should be entirely seamless, and every UX change (even if it's an objective improvement, which this is clearly not) from what MS is currently doing represents lost users; the value comes from ethics, not software, so don't fix what isn't broken.

This isn't a huge issue, but it's one of the larger issues why FOSS alternatives are not often as well received as their proprietary counterparts (see: unix). Consumers/users should be the first/only consideration when designing user-facing software, but it's a rare sight to see in FOSS. I wish more FOSS developers cared about the software instead of the code, because the difference manifests in decisions like this.