Did you get a browser error when trying this? It might be because you left the www in the URL. I had to remove that and replace it with old, and it works. The rest of the link structure is the same on both old and new reddit. I even tried it from a VPN just to be sure it wasn’t seeing my logged in cookies, and in a private browsing window where RES isn’t allowed to run. Worked fine.
It also feels like their insistence is doing nothing but hurting them. The average consumer who doesn’t know the difference between a local account and a Microsoft account won’t know or care about MS doing this.
But the users who do have a preference and do want a local account are just going to be irritated at it and give them bad press. They’ll eventually figure out how to make a local account anyway and it may be the push they need to migrate off of Windows.