> Are you referring to generators?

Both I guess.

Main thing is https://learn.microsoft.com/en-us/dotnet/api/system.collecti... which seems to be everywhere in the language and the library.

> I believe the same justification applies here, it's mainly syntactic sugar, and can result in certain undesired behavior by bypassing constructors where validation can happen.

This is mostly due language design. Java heavily relies on properties and provides no facilities for them. Hence the builder pattern instead of object initializers.

In C# object initializers synergize with properties: https://learn.microsoft.com/en-us/dotnet/csharp/programming-...

> The approach they took does not need any extra syntax.

You mean it needs 15 lines whete C# needs one? ;)