Very important overall point that we should be concerned about violence from either side of the spectrum. The left and the right need to universally agree that political violence isn’t an option.
I don’t agree, however, with you equating a political disinterest in gun control as an advocacy for political violence via silence. This election saw the furthest left and furthest right politicians as viable candidates in a long time (possibly ever). The closer you get to those fringes the greater chance of political violence. The president* and his surrogates actively courted that violence, but to say the same about Bernie is a stretch I’m not comfortable with.
Truthfully the left could benefit their cause greatly by moving more center on the gun issue. I personally believe in stricter him control and that gun violence is a big deal, but is it a bigger deal than the minimum wage? Universal Healthcare? Tax reform? Criminal Justice reform? Voting Rights Protections? I would let the GOP have a ten year ban on assault weapon bans for a victory in any one of those columns. Plus, by moving center it could legitimately attract more voters who use gun rights as a linchpin issue. There is only so much political capital to go around and gun control I would argue should be lower on the agenda. There are a ton of gun deaths each year, but how many people are uninsured or under employed!