From my perspective (as a foreigner who has spent a lot of time in the US) I think the second amendment has a lot of downsides, but I find myself siding with the gun rights crowd on principle, because the anti-gun-rights people seem to be so dishonest in their methods. The US Constitution provides a mechanism for amending the US Constitution, so if you don't like what the US Constitution says then you should be moving to amend the US Constitution, not moving to ignore it.
If gun rights opponents would just come out and say "Let's amend the Constitution to repeal the Second Amendment" then maybe I'd agree with them, because they'd be making an honest proposition to do things in the legally correct way, and they'd have to clear the appropriate bar to make it happen (incidentally I think the US Constitution should be like the Australian constitution and not changeable without a referendum, but that's another story).
But it seems that gun rights opponents almost never take this tack -- they're always trying to just straight-up ignore the US constitution.