Tom Cruise, Stacee Jaxxing it hard. (David James/Warner Bros.)

As the weekend box office results have already revealed, “Rock of Ages” didn’t do so well in the movie-ticket-selling department. Specifically, it debuted in third place, behind “Madagascar 3” and “Prometheus,” earning a decidedly not-rockin’ $15.1 million.

There may be a temptation to blame this development on shirtless Tom Cruise (see above), the man who, as Stacee Jaxx, demands in “Rock of Ages” that we pour some sugar on him, in the name of love.

“That movie tanked because of Cruise,” you said to yourself as you scanned the box office results, a potent hit of Cruise schadenfreude already coursing through your veins. “This is proof that he is neither hot nor sticky-sweat, from his head to his feet.”

Well, as someone who once served as the defense attorney in Tom Cruise Court and therefore feels obliged to support his career choices for reasons that even she doesn’t always understand, let me just say that this is so not Tom Cruise’s fault.

“Rock of Ages” is the sort of movie that appeals to an extremely limited slice of the movie-going public. Who is that slice? People who actually remember the Pat Benatar, Poison and Foreigner songs covered in the film, as in were alive when they were initially released and actually thought they were legitimately awesome because it was the ’80s and sometimes our tastes back then were a tad questionable. (We did this to the bottoms of our jeans back then, okay? Clearly all of the blood did not make it from our ankles back up to our brains.)

Also part of the slice: people who like musicals (or at least “Glee”) and are totally cool with watching movies in which people spontaneously burst into song. Also necessary to fit into the “Rock of Ages” target demographic: an ability to spend a consistent amount of time looking at Alec Baldwin in this wig.

(David James/Warner Bros. via AP)

As you might imagine, that’s a pretty limited number of people. And many of those people — including myself, who was on vacation last week and missed the “Rock of Ages” press screening and will therefore have to spend her own money to see this movie at some point (oh, the sacrifice!) — probably didn’t rush to see it on opening weekend. Why? Because we’re old. (As Box Office Mojo points out, 74% of this movie’s audience was over the age of 25.) We spend our weekends running errands at Target and making sure our kids don’t ingest anything lethal while we’re making dinner. We are busy.

Tom Cruise understands this. The man turns 50 in two weeks. Do you hear me? Fif-ty. And look at him.

(David James/Warner Bros. via AP)

No, don’t look at him there. He looks ridiculous. This was the other problem with “Rock of Ages”: The whole thing looked ridiculous. And people don’t have money these days to take a chance on potential cinematic train wrecks set to the tune of REO Speedwagon.

Anyway, look at Tom Cruise here.

(Stuart Wilson/Getty Images)

Fif-ty. I mean, what? He’s still wearing Maverick’s sunglasses from 1986 in that picture and it still works somehow.

Sorry, I got distracted. The point is this: “Rock of Ages” was a dicey proposition for most moviegoers. The ones who already bought into the idea of “Rock of Ages” because they saw the stage show may not have supported the notion of Cruise in the role Constantine Maroulis once played.(Correction: Maroulis didn’t play Jaxx in the original Broadway production, James Carpinello did. Apologies for the error.) That’s the one way in which Cruise may be responsible for the movie’s failure. But everyone else was either turned off by the premise, or knocked off the fence after reading the mixed reviews.

Will this box office slip affect Cruise’s career? Oh, heck no. Because Cruise is too smart for that. When he plays an above-the-marquee role — one that announces “This is a Tom Cruise Movie” — he usually does so in films that will likely be met with some degree of box office success. (See “Mission: Impossible — Ghost Protocol” or “War of the Worlds” for examples. Also, see “Knight & Day” for an exception to that rule.)

But when Cruise decides to do something off-type or semi-daring — see “Rock of Ages,” “Magnolia” or “Tropic Thunder” — he often does so as part of an ensemble. That way if the whole thing tanks, he doesn’t have to shoulder the blame by himself. This is what smart mega-movie stars do.

It’s actually what successful people do in general: take credit for the guaranteed successes and share the blame for the failures. It’s what your boss does, too, and it’s totally annoying, isn’t it?

Anyway, just to reiterate the bottom line: “Rock of Ages” is not Tom Cruise’s fault. I, Jen Chaney, swear that this is true, on a stack of Def Leppard albums, including “Pyromania,” which was totally their best one.