I honestly went and read those release notes just to check if they're using this transition as an excuse to make the game less cross platform.

Why would they do that? They specifically made bedrock edition so that the game could be more cross platform, which has worked extremely well for them financially.

Java edition has never been playable on anything other than Windows, Mac, and Linux, porting an SDL version onto any of those is extremely easy.

Getting everyone on one platform is a much better model for Microsoft than trying to resell you a copy on each device.

How does that make sense? SDL is extremely portable?

Or once again change the login system in some way that locks tons of people out