If there wasn't a problem with short selling, there never would have been a halt to it.
It was just the pressure from hedge funds that got the halt removed.
And financial institutions short more than most, sometimes to hedge, but usually to do exactly what they set out to do, take advantage of an already shaky situation.
When Lehman Bros started getting hurt by the MBS (mortgage-backed securities) position and the CDS (credit default swaps) they owned, short sellers attacked them in a big way. This is not my opinion and several very factual articles on the situation, easy to find.