Those things aren't exclusive to or indicative of a capitalistic society. The latter two reasons you describe also exist in authoritarian socialist and communist countries, yet those don't lead to mass shootings.

In fact, there are capitalist countries that have easy access to guns that don't experience mass shootings on the scale of the US. Look at Canada, for example, who rank 7th in gun ownership per capita but have experienced four total mass shootings compared to 101 in the USA. (sauce: https://wisevoter.com/country-rankings/mass-shootings-by-country/ and https://en.m.wikipedia.org/wiki/Estimated_number_of_civilian_guns_per_capita_by_country)

I don't think capitalism is the best system, especially not on its own, but none of the responses I've gotten have argued why capitalism is the cause of mass shootings. There are way too many cultural and historical factors involved to say that it's exclusively the fault of the economic structure of the US.

You guys can all downvote as much as you want but it seems no one actually has anything more to say than "capitalism bad" so they harvest some internet points.