The point is that there is at least one gun in 1/3 US households. So someone living in one of those households can have a passing thought of suicide, and then act on it irreversibly in a matter of minutes. You're welcome, I guess, to frame that in terms of limiting someone's freedom, but it doesn't have to be about the government taking away the guns; maybe there's just an argument there that having a gun in your house is unwise given the potential impact it could have on future you or your family members. An alcoholic doesn't keep beer in their fridge either, because the potential for self harm is too great.