Democrats have been envious of the opposition Republicans had with 0bamacare. I don’t know of an instance where zero members of the opposition party supported a major initiative in congress.
Democrats fear the fallout resulting from the exposure Benghazi represents.
The difference is Republicans opposed 0bamacare based on individual political philosophy whereas Democrats can only oppose a special select committee based on politics and winning elections.
It shocked me that no GOP voted for it. It was great “whipping” up of votes (if that is the term).
When you see any group anywhere in total lockstep the only most likely scenario is intimidation and or a group that has been beat into submission. Usually a corrupt group.