I’m also still mad at them for competing against amazing stuff like ServiceStack (a real OSS project from the community, and the best way to run REST APIs I’ve ever seen) with “official” but worse stuff like ASP.NET Web API. They do this a lot, some OSS gets popular but instead of embracing it, they make a half-assed ripoff, proudly proclaim it “official” on conferences and all the C# devs jump off the cliff like lemmings, and the original OSS project dies/stagnates. MS might have officially embraced Open Source but they’re absolutely awful at fostering an OSS community.
But .NET itself is amazing! There’s this weird misconception in Microsoft land that if you choose .NET you must also use all MS’s half-assed libraries. Just use Postgres! Use a lean ORM like Dapper, use Redis, use whatever you want from the wider OSS ecosystem. There’s nothing about C# that forces you onto Entity Framework. Get out of that red polo shirt and look around, there’s a lot of cool stuff out there.