I think it's safe to say the Mt. Gox dumping has some influence, but the effect from the FUD it causes is much larger than it's actual effect.
It surely has an impact on the market, but at the same time it's quite pathetic. People let themselves get controlled by something that shouldn't be able to cause any damage to the market at all.
If they just acted in a way they were genuinely caring about Bitcoin and the victims they supposedly are selling their coins for, they would have sold their coins in the way they should be sold, and that's through OTC.
I am fairly sure that they sell on exchanges because it allows them and their other criminal partners to dump the market down, and thus are guaranteed to buy Bitcoin privately on much lower levels.
They sold their own coins at the top, used the MtGox coins to tank the market back resulting in a massive correction, and they at a later point bought back. They made tens of millions over the back of innocent people.