Why use Mahomes as a comparison?
This tactic is what I call a "subliminal gadget." It's designed to compare two objects without declaring that you're comparing the two objects. But because one object is so obviously (in this case) superior, to attach the other object to it subliminally suggests that the two are the same or the inferior object is actually better than the one it is being compared to.
If you want to make a point that Dak is a good quarterback based on how many 400 plus passing games, you widen your list beyond Mahomes. That way it dilutes the comparison among the many rather than to the one - who, in this case, naturally commands the focus.
The effect is like comparing anyone with that guy who ultimately caused World War II. Any arguments about that guy building roads and improving his nation's infrastructure will always be overshadowed by the other heinous thing he did do.
Similarly trying to compare a quarterback with no rings and who hasn't even sniffed a NFC Championship Game to a quarterback who has won A ring or multiple rings or who at least got his team to the AFC Championship Game 4 consecutive years will fall on deaf ears.
People should know not to make such a comparison.
Similarly, posters should know not to compare Dak with Mahomes and definitely not Brady (which has been done in this forum).