Even though I agree with him about Eminem not being the #1 rapper of all time, his analysis is weak. This is what he should have said.
Not to get racial but hip hop is a black art form, so it’s a little weird giving the title of “best rapper” to a white guy. Nonetheless, a major part of hip hop aside from lyrical skills is being ground breaking and “bucking the system” and Eminem is certainly all of that -it’s just that the “system” he “bucks” is making music most Black hip hop listeners would listen to. Read that last part again slowly.
And that’s pretty much the reason why Eminem isn’t the greatest rapper of all time.