We think it's unlikely that `rubygems/defaults/operating_system` could be shipped with a SyntaxError so StandardError could be better choice to prevent "false positives" errors.
https://github.com/rubygems/rubygems/commit/1f73e784dd
When loading `rubygems/defaults/operating_system`
- we want to keep it silent if the raised exception is a LoadError
- we want to print a message in other cases and ask users to report the issue to their OS support.
Ruby 3 comes with special error handling for loading `rubygems` and it will show a warning when LoadError exception raised for requiring 'rubygem'.
Because of that, we decided to leave the LoadError scenario as it is.
Reference: d1998d8767/gem_prelude.rb (L1-L5)https://github.com/rubygems/rubygems/commit/0a97e12fe1
