It also appears to be a nonsensical complaint in general. Why abuse .class files for data storage when you can choose any data format you like?

I've only seen this pattern used in contexts, where there is no filesystem to begin with.

> Why abuse .class files for data storage

The only alternative is to have the data in a separate file, which needs to be available, read in, and parsed. .NET/CLR provides a mechanism to bake large objects into the assembly and I don't see that as abusive. It's way more convenient when you can treat the object as being “just there”.