I subscribe to a lot of comics to be delivered in my mailbox (14 to be exact). They provide a welcome distraction from the sameness of my day and help me lighten up. The Dilbert strip from Monday 18th 2019 was in extremely poor taste and made me wince.
Even in jest, it targets a characteristic that is protected. Although, what Mr. Adams has portrayed might reflect reality, it might also justify this in some peoples' minds that it is OK to joke about peoples' ages as long as you are not serious.
As a part of my corporate training, I have undergone a lot of managerial trainings that has sensitized me in how things can be interpreted in a way that may not have been intended. I can see this thing happening in an office and some young worker get into trouble over this which is completely avoidable.
I urge young people to not joke about this and would expect Mr. Adams to remove this cartoon and not repeat that again.