The answer was pointing out how much of 'gun violence' is gang violence, which is a valid point but seems some gloss over the gang problem so they don't look racist, so they just tell you you're 'downplaying' for mentioning it.
That said, it's absolutely disingenuous for 2nd Amendment advocates to point fingers at marginalized groups (trans, the mentally ill, POC, etc) as the reason for mass shootings. This is a standard Conservative trope; point fingers at 'the others' in order to ignore the root cause of the issue which would most certainly reduce the severity and frequency of these happening in the US.