Why shouldn't congress push more laws in the wake of the Las Vegas shooting?
First, the gun that Stephen Paddock used to commit his heinous crime was likely already illegal.
As Sean Davis explains at the Federalist automatic weapons (or machine guns) are already banned or almost unattainable under existing federal law.
Secondly, the concert was a "gun free zone." All guns were already banned there.
Thirdly, Paddock would have had to have done a lot of work beforehand to prepare for this unspeakable act. There is nothing that Congress could do to stop someone as committed as Paddock was.
Finally, Ben Shapiro of the Daily Wire explains that making policy on the heels of a terrible event is usually a bad idea.
Gun control laws remove guns from law abiding citizens, so that they can no longer defend themselves, and emboldens criminals, who won't follow the laws anyway.