I think symfony developers are still good professionals, given the size of the project and the amount of contributors, having an error or not having a test case for something specific could be forgiven, I would reply that errors and bugs can slip in a codebase, I guess it's more important to create a test case to double check that a bug doesn't re-appear in the future after it has been fixed?

I mean I fail to understand what are you trying to say, someone stops being a professional as soon as it hasn't covered a test case?

Or are they kids just for having slipped a bug? Despite their work powers a lot of companies software (including the ones I work for)

Are you just trolling?