Being a sports fan, something has been bugging me for a while. It’s when announcers or sportswriters refer to a team by the plurality of their mascot. I was reminded again today when an article in today’s Sports Illustrated began with the line, “The Miami Heat was desperate.” Shouldn’t a sports team, being a group of people, be referred to as such? This happens all the time, so maybe I’m just really clueless.
In the UK, teams are generally referred to in the plural (“Manchester United were terrible…”). I think that the version you mention is grammatically correct, though – when I was at school, I was taught that in that kind of sentence there’s only one team, so it’s singular. Manchester United may have many players, but there’s only one actual team.
But “the Celtics WERE desperate.” (just an example, folks) I think they just take the singularity or plurality of the name and follow grammar rules. But “the Jazz WERE desperate,” too. Jazz is singular. English is a difficult language with all the exceptions. But I would not go to SI for grammar lessons.
I agree totally with the OP. A sporting team is one thing, and should be spoken about in the singular. The plural form grates on my nerves every time I hear it.
I think we’re fighting a losing battle here though. 
It depends on the use of the team name.
“As usual, TV you are making no sense,” I hear you cry.
But let me explain. Team names like such words as “jury” “group,” and “flock” are referred to (by grammarians) as collective nouns. Depending on the use, they may well be either plural or singular.
They are singular when the group it names acts as a single unit. “The Magic has won every game.”
However, they are plural when the group it names acts as individuals with different points of view. “The Magic were fighting in the locker room.”
So technically, the plurality of such team names as Lakers, Rockies and Sabers should have little to do with the verb usage, but most people don’t know about collective nouns so they generally go with what the ending of the team name is.
Technically, the verb usage is often incorrect, but hey, American English is an evolutionary thing. So other than a 100,000 or so retired English teachers (who usually don’t read the sports pages anyway) and my copy editor who keeps ripping his hair out over such things as incorrectly used collective nouns, who’s hurt? No harm - no foul. (The one that really drives him crazy is when sports writers refer to “runs batted in” as “RBIs”. He always screams, “That’s like saying they are ‘runs batted ins’!”)
TV
The Yankees is winning the game? The Mets is down 3-1 in the series? The Jets has no chance of making the playoffs?
I can never figure out how to refer to a single Red Sox or White Sox Player. He was a Red Sox his whole career? He was a Red Sock? He were a Red Sox? 
OK OK, you got me. I hadn’t considered names which incorporate a plural.
Damn, I love this language. 
So would he prefer “RsBI”?
I don’t see how plural proper names create a problem. If you’re dealing with a girls’ lacrosse team, you say “the team is from Holyoke” or “the girls are from Holyoke.” If the team name is a plural (“the Girls”), then it refers to the players, plural, not the team, singlar. The “Yankees” are several singular Yankee(s). If the name is singular, it refers to the team, singular, not the players, plural. The Crimson Tide is one team, and the team name reflects the sigular nature of the team, not the plural nature of the players. The only problem now is how to classify names such as “the Heat” that don’t normally take a singular or a plural, and I think those names ought to be outlawed on the grounds of inanity anyway, thereby dodging the problem. 
Although we do know from Glen Frey that Heat is singular, 'cause the heat is on.
My $.02