I mean, the gun thing is (and has been for a long time) damn near farcical. The sheer fetishization of a thing so dangerous, kept afloat by a religious dedication to a piece of paper written up centuries ago (as though it would remain perfectly relevant and meaningful after all the changes in technology and civilization we've been through and will continue to go through). And any attempt to change the status quo gets steamrolled by an organization that is rolling in money because of them, that bankrolls the politicians and does its damnedest to convince everyone that they need these things that they are being occasionally slaughtered with.
But masculinity? Yes, that's certainly part. It's exactly why toxic masculinity is a phrase. Toxic because it isn't just harmful to people who aren't male, but harmful to males as well. Obviously individual circumstances vary, not everyone goes nuts with a gun, etcetera. But it's why the suicide rates of males are so much higher than females. It's why mass shootings are overwhelmingly done by males. The male experience is driven by the idea that no matter what happens, you must be manly. Repress emotions, no crying, be strong, be cool, don't be a girl, and enforce it all on the people beneath you. Not everyone can handle this (nor should they have to), and society's disapproval of that only exacerbates any issues a person might already have. It's all driven by the sentiment that femininity is bad and should be rejected. And that hurts everyone.