The reason the Left is against gun ownership is because the basis of their philosophy is that there are no standards of behavior, no good and bad lifestyles, no cultures that are inferior to other cultures.

Given that basic belief, gun control is a necessity. They fully realize the damage that such an approach can cause and therefore seek to limit that damage.

Welfare programs and abortion clinics derive from that same approach as well.

In the name of greater liberty for all they seek less liberty for everyone.