***Are the patriots the greatest team in nfl history?*** not is the patriots...
Since we're playing grammar police, WI Mike was actually correct. He's not talking about literal patriots, or a group of specific Patriots players. He's talking about an NFL franchise
named the Patriots. You could name that team anything you want. The fact that the franchise uses a proper noun in its plural form does not change the fact that he is referencing the franchise as a single entity. Therefore, the singular verb "is" is correct. Of course, as a colloquialism, your choice of words is fine as well in day-to-day speech, assuming your audience knows your meaning.
Example:
Is "The Goonies" a good movie?
Are "The Goonies" a good movie?
Which sounds right to you? Same principle. Now if he was referencing a specific group of Patriots players, or a specific year's team, then plural would be correct.
"Are the Patriots playing this week?" is correct because it refers to a specific group of players who carry the "Patriots" name. But again, Mike was referring to the franchise as a whole, independent of any specific players, making "is" the correct verb in his context.
The flip side is even odder sounding. Take a group with a singular name for example:
"Rush is an awesome band." Nobody argues whether "is" is correct because it is a reference to the band as a whole. However...
"Rush are awesome, especially Neil Peart." Since the sentence references individual members of Rush, the plural "are" is technically correct, although nobody would ever complain if "is" was used in its place.
Bottom line, while your version of the question posed in this post is perfectly acceptable in colloquial speech, Mike was not incorrect.