Which is neither true nor totally fair.
The thing you have to remember is that Depp pretty much does what he wants.
Which is why films like Dead Man exist, even though no one saw it, and the Pirates franchise is there - even though most right-thinking people wish it wasn't.
And it's almost certainly why Black Mass exists.
Playing the role of Boston gangster Jimmy 'Whitey' Bulger was never going to be easy - his victims' families are still rightly grieving, and it's so recent there hasn't been time for a Krays-esque aura to develop.
So someone who doesn't give a toss what the critics are going to say was always going to be the best choice to play a man who seemed to kill half of Boston from the mid-70s to the early 90s.
Getting any sympathy for this man was always going to be a hard sell.
So it's to Depp's - and the film's - credit that they don't bother, portraying the man as the heartless killer (and drug dealer, gun runner, racketeer etc etc) he was.
The other problem is, of course, that in doing a gangster film you are automatically putting yourself up against The Godfather and Goodfellas.
Every genre has it's cornerstone films, the ones that define the styles and themes by simply being the films you automatically think of when you hear the word.
And up there Black Mass isn't.
To be fair, it's not trying to be. But that doesn't stop the comparisons being made.
It's not glitzy, it's not glamourous. It's fairly brutal, the violence is not shied away from, and the portrayal of Boston (always known for it's gangsters) is as unflattering as you would hope.
In fact, it probably has more in common with the excellent A Most Violent Year - but even then, it seems to fall short.
The problem, I think, is that the whole film feels muted. Like everyone's underplaying it.
And I think this stems from Depp.
From the off, this is a very considered performance. Recent outings have all seemed to borrow from Captain Jack Sparrow, and it's clear he's doing something totally different here.
The problem is, as the lead character, as he underplays things so everyone else has to tone things down.
So we get less Kevin Bacon, less Benedict Cumberbatch, less Dakota Johnson (although to be honest she could just still be in post-50 Shades shock).
This slightly removed, distant, muted feel is hard to grasp or understand until Corey Stoll turns up as the new DA in town.
Suddenly we have someone giving it energy, presence, owning the scenes that he's in - there's a very clear step-up when he's around.
Tellingly, he doesn't share any screen time with Depp.
All of this only serves to add a level of disappointment to what could - and indeed should - have been a gritty, nasty telling of the life of a loathsome human being.
What you want is to come out of it feeling almost violated, like you need a shower and a change of clothes.
Instead you just feel flat, like you've just missed out on something that could have been great.
The performances are all perfectly good, if a little restrained, it's shot well, Boston looks like the slightly forgotten city it was back then... It's getting close to the mark all over the place.
But then little things let it down.
I'm pretty sure Jimmy gets called John at one stage, which you notice because it doesn't happen at any other point, and the attempts to make the pop-music references iconic definitely falls short.
Then there's the disappearance of one of the characters.
You don't notice straight away, but about halfway through you suddenly realise you haven't seen someone for a while. They've just vanished. Poof. Gone.
AND NO ONE MENTIONS IT.
And what the hell was Peter Sarsgaard's character doing talking to Boston's finest when he seemed to live in Florida?
And why does no one's hair change in 20 sodding years?
The structure of the film, however, is a plus.
Using a faux-documentary style, you leap between the now and the then effortlessly, fleshing out the story without giving too much away.
But it's not enough to save the day.
As I said earlier, this should - and could - have been a much nastier film. Make it an 18 (R in America I'm guessing) and you'll get a more visceral experience.
But as it is, you get everything dialled down slightly, leaving you feeling a bit 'meh', a bit unmoved.
Still, Depp's in heavy make-up and it's award season, so it might not have been a total waste of time.