I couldn't disagree more.

How do you expect junior programmers to become senior ones without help? Having automated guard-rails saves a large amount of your senior devs time by avoiding them having to pick such things up in code review, and you'll find the junior programmers absorb the rules in time and learn.

Several of the examples are nitpicking naming, this is exactly what should be automated. It's not like even experienced people won't accidentally use camelCase instead of PascalCase sometimes, or maybe accidentally snake_case something especially if they're having to mix C# back-end with JS frontend with different naming conventions.

Picking it up immediately in the IDE is a massive time-save for everyone.

The "There is an Async alternative" is a great roslyn rule. Depending on the API, some of those async overloads might not even have existed in the past, e.g. JSON serialisation, so having something to prompt "Hey, there's a better way to do this!" is actually magical.

Unused local variables are less likely, but they still happen, especially if a branch later has been removed. Having it become a compiler error helps force the dev to clean up as they go.