And I agree - GPA is pretty irrelevant to anything in the business world. All it proves is that you can play by the rules in the school system - not a real indication of your experience, skills, or relevant knowledge.
For every hiring manager who takes the approach that anyone putting their GPA on their resume is an asshole or an idiot, there's three others who think that there's something wrong with a junior applicant who doesn't put their GPA on their resume.
Unless you tell the applicant what you want to see, they have no idea which of these two hiring managers you might be. Instead of downmarking people for having the audacity to present this information to you, perhaps you could just ignore it?
[1] Which the hiring manager in this thread has unironically demonstrated.
This more for undergrad as most people are expected to pull a ~3.8-4.0 in grad school making the number meaningless.
PS: On average I suspect it's a net gain for your first job, but adding a GPA after that is likely a larger risk than you might think.