It's true, check it yourself. There is not a single credible analytic body I am aware of that endorses what you said. I mean it, not one. The idea that the government caused the mortgage meltdown is an opinion held almost exclusively by the right wing in America, and nowhere else.
While I feel the need once again to mention that such an analysis is not supported by credible economic bodies, the fact remains that regardless of what the market conditions were like, managers in those companies took actions to gain short term profits at the expense of long term viability. This is hardly the only example of this, but it just shows how short term profits can certainly drive long term destructive action.
There is a crazy ideology against government that blames it from the housing bubble to the little girl being given a carton of milk as tyranny.
It's more complicated than black and white. Fact is, the government is very involved in these things, and can do some harm while doing a lot good crazies deny.
I've seen a good book - I'd go find the title but seems like a waste of time - explaining the history of this, and there was, as one big part, a sort of competition between the head of a leading financial company who created a lot of the damaging derivative housing products, and the head of Fannie or Freddie, who was sort of forced to take a big part in them to keep his agency important - the private company was pretty clearly the one initiating the problem, but the Fannie/Freddie side helped make it a lot worse.
It's interesting to look at how bad it was that these sort of power contests could cause the harm they did - how broken regulation was and is - but right-wing nuts are nuts.
Even the issue of that broken regulation goes from 'more better regulation is needed' to right-wing nuts saying the fix for inadequate regulation is less regulation.
Without the private sector criminally creating incredibly profitable harmful derivatives, there wouldn't have been a problem with Fannie/Freddie doing the wrong they did with them.
But in the hands of a Republican presidential candidate, 'the financial crisis was the government's fault'.
Similarly, the problems caused by bad fed policy, like that of right-wing ideologue Alan Greenspan, are problems - but the right-wing nuts just say 'abolish the fed' as if there weren't constant major financial crises by the lack of government involvement; they are ignorant of how the only stable period was with the FDR-era rules.
They only understand a simple response like 'get rid of the evil governemnt!' that would actually cause big problems.