[kstrauser]

"We don't have enough test coverage to ensure that we're generating RFC-compliant output" is objective. That's not a personal though, feeling, or opinion. If you wish, you may generalize that to "we don't have enough tests to catch an error that made it into the shipped product".

[imanaccount247]

That would only be objective if it were possible to have enough test coverage to ensure that. But that is not possible. So it is purely a subjective question of how much test coverage person A thinks is "good enough".