If you want to attack Trump, go after the fact that he is an ignoramous who was speaking about defaulting on the US debt because it worked for his casino, or that he has many failed businesses, that he lies constantly, etc.
Don't go after him for being shrewd enough to see that housing was in a bubble and try make money from the evenutal pop. It just highlights something where (he says) he got something right. He was not in gov't and how no power at that time to do anything about it other than try to profit from the downturn.
Again, Trump is such a flawed candidate - the problem is that Hillary can't go after him on his major issues because she is the same/worse on many of them.
I agree with Taibi, this was just a dumb ad.