Titles and hyperbole aside, what did The Source Infinity Man do that was so impressive? All of his kills except for Orion were assassinations, he didn't rip through Superman like Tyrant would. In fact Adam Warlock could have reproduced every assassination that he did.
You have to admit, that Superman held his own when they fought, and it was so apparent that the Infinity Man had to put him in a force bubble to stop him from what appeared getting his ass handed to him.
IM didn't want to hurt Superman, and The Source himself checked on his health and sent him back home.
As for what he did that was so impressive, he stood against Mr. Miracle with the Anti Life Equation, who was powerful enough to destroy the Source Wall. Historically, it takes multiple skyfathers simply to penetrate it.
Can you prove that the Infinity Man was not trying against Superman? I can't.
If Superman were up against just one true Sky Father, and not several he would have been dominated with ease, but that wasn't the case. Tyrant would have put Superman on his face with 2 hits, and yet this over-hyped version of the Infinity Man was unable to remove a High Herald? C'mon, I thought proof outweighed titles and such. Maybe I should start rethinking my position on Roma then... hmm.
Easily would have meant something more along the lines of the fight being completely one sided as it was when Tyrant mopped up a room filled with Heralds, with a smile I might add. Whereas Superman gave back as good as he got, and forced IM to encase him in a containment bubble. Superman even hurt him as you can see in the book when IM shrieks in pain from a solid right cross.
Too bad no one has any scans to show how well a Herald tier did against Infinity Man.