The writer didn't do anything except say that going undefeated doesn't necessarly make a team the best of all-time. And that's true. Most serious football fans wouldn't rate the '72 Dolphins as the GOAT, as they had a rather weak schedule (only played 2 playoff teams I think) and weren't particularly dominant in their wins. That distinction usually goes to the '85 Bears.
But the writer doesn't go beyond his blanket statement (16-0 does not equal best ever) and give any good reasons why the Pats wouldn't be the best ever, aside from his homerisms about how the '74 Steelers would "squish" them. Not entirely convincing.
IF (and admittedly that's a big "if") the Pats go 19-0, it will be hard to argue against them being the best ever. Already this season they have beaten; last year's Super Bowl champs (who weren't that injured...just ask Brady what it's like to play with a truly depleted team) and arguably the best team in the NFC. By the end of the regular season, they will likely have beaten 6 or 7 playoff teams, and look like they're going to break a lot of offensive records in the process. If greatness is to be measured by dominating the best the NFL can throw at you, the '07 Pats are tough to top...even by the '85 Bears.
Now, the writer takes a hypothetical (two teams from different eras playing each other) and declares the Steelers better, presumably because they hit harder or had more HOFers. Well, I think the hard hitting would be handled reasonably well by a Pats team that is significantly bigger. And its not as though the Pats are a finesse team....just watch Welker catch a ball between the hashmarks. And in terms of who has the most HOFers...that's just a stupid way to measure a team, particularly when you're comparing one team from before the salary cap era to one team from the cap era.
Anyways, no one likes a dominant team - especially if they're from Pittsburgh and the dominant team is not the Steelers. So crap like that author wrote is expected....but it just comes off as some insecure fan who feel that his team's place in history is being threatened.