Agreed. The last thing in the world the Democrats want these days is for anyone to mention gun control. They know they're in for an ass kicking in November because if Biden, inflation, gas prices, etc. Throwing gun control into the mix would do nothing but guarantee that in the close districts the pro gun voters would come out of the woodwork and vote against democrats.
Might see some changes at the state level, given that New York is pretty much a democrat-controlled state. But then again, they already have pretty strict gun control laws in NY so it's hard to say what they could do that they haven't already done.
EDITED TO ADD: 23 years after Columbine, with VA Tech, Sandy Hook, Las Vegas, the Pulse Nightclub, etc in the rear view, I think the political impact of a mass shooting is almost zero now. All it's going to do is reinforce whatever positions people already had. If they're anti gun, this isn't going to make them MORE anti gun and if they're pro gun, it isn't going to make them MORE pro gun.
People have already chosen sides and a mass killing isn't going to make them change.