Going into this reply with the understanding that we both know that a perfectly legal reason for firearm ownership and use in the USA is self defence.
So with that in mind, shooting isn't easy. And people don't just stop because you shot them once, or twice. Just take a look at the infinite examples where actually trained professionals have had to fire multiple accurate rounds to stop a threat.
The issue isn't with the weapons themselves (and contrary to your comment, belt fed weapons are no less legal to own than any other semi auto weapon) it's with the restrictions to the individuals that can own them. The checks aren't stern or thorough enough.
If you take a step out of your US centric view for a moment you'll realise that many countries in Europe have civilian gun ownership laws permitting all the same types of rifles and pistols and shotguns as the US. With all the same standard capacity magazines/optics/accessories. And yet very little to no firearm related deaths outside of organised/gang crime.
It's important to maintain perspective. You become extreme to the opposite then all it does is increase extremism and you achieve nothing.
Edit: downvotes. Cool. Where am I factually incorrect or haven't added to the conversation?
Exactly. It depends on the severity of the negative outcome.
It's one thing to be confident in directions, it's another to be confident in a pre flight check list for a 737. That's why there's appropriate guidelines that dictate how to conduct the latter.