My issue with his argument, and all that make it based that guns are not the problem but poverty/capitalism/GQP/mental health etc etc. is that at no point is the US doing anything to avail those issues either, so we reach an impasse, except we can discern more answers from looking externally:
Australia, Canada and UK have not abolished any of these, with varying degrees of efficacy on assisting health, the rest (supplementing GQP with our conservative nuggets), and the firearm legislations we have implemented and continued to implement have lead to almost non-existent mass shootings, suicides and homicides dropped as well, but did not eradicate them of course, so we can draw on a cursory glance that health and guns have a variable effect POTENTIALLY. Since the US has issues with underfunding, and having even more funding pulled from health access.
https://www.vox.com/23142734/uvalde-...olence-control
https://www.vox.com/policy-and-polit...land-uk-canada
https://www.cfr.org/backgrounder/us-...al-comparisons
Another issue is that if someone wants to claim that guns were EASIER to get their hands on, but less mass-shootings happened, my counterpoint is what was gun ownership levels? They may have been easier to get your hands on, but did people actually bother to do it? However, that point is moot; because at the moment, nothing is being done at all, outside of tarts and pears. If you are only attempting to obfuscate against a multi-pronged approach to prevent, or at least majorly reduce the numbers of mass shootings, and to a lesser extent, homicides and suicides, you are indirectly complicit, and see, at least in the short term, these deaths are just a price to be paid.