Sebastian asks, "Why is it that anti-gun folks love pushing bills in response to tragedy that would in no way shape or form have even remotely prevented it?"

It probably was a rhetorical question but it fit in so well with the book I've been listening to, Philosophy: Who Needs It by Ayn Rand, that I felt compelled to offer some answers.

There are several plausible answers to Sebastian's question and they are not exclusive, it could be several of them are correct depending on the individual and the tribe they belong to. More on "the tribe" later but first a quote from Rand, page 9:

Those who seek to destroy this country, seek to disarm it--intellectually and physically. But it is not a mere political issue; politics is not the cause, but the last consequence of philosophical ideas. It is not a communist conspiracy, though some communists may be involved--as maggots cashing in on a disaster they had no power to originate. The motive of the destroyers is not love for communism, but the hatred for America. Why hated? Because America is the living refutation of Kantian universe.

Today's mawkish concern with and compassion for the feeble, the flawed, the suffering, the guilty, is a cover for the profoundly Kantian hatred of the innocent, the strong, the able, the successful, the virtuous, the confident, the happy. A philosophy out to destroy man's mind is necessarily a philosophy of hatred for man, for man's life, and for every human value. Hatred of the good for being good, is the hallmark of the twentieth century. This is the enemy you are facing.

And from page 41, where the tribe reference originates in this post:

As an example of the principle that the rational is the moral, observe that the anti-conceptual is the profoundly anti-moral. The basic commandment of all such groups, which take precedence over any other rules, is: loyalty to the group--not to ideas, but to people; not to the group's beliefs, which are minimal and chiefly ritualistic, but to the group's members and leaders. Whether a given member is right or wrong, the others must protect him from outsiders; whether he is innocent or guilty, the others must stand by him against all outsiders; whether he is competent or not, the others must employ him or trade with him in preference to outsiders. Thus a physical qualification--the accident of birth in a given village or tribe--takes precedence over morality and justice. (But the physical is only the most frequent apparent and superficial qualification, since such groups reject the nonconforming children of their own members. The actual qualification is psycho-epistemological: men bound by the same concretes.)

With that background I offer several possible answers to Sebastian's question. All come, perhaps in a somewhat obscure manner, from the first few chapters of Rand's book.

1. Because the gun is a means of individual power and threatens the power of the collective. The more power an individual has the less it needs the collective. They believe the collective is more important than any, and in fact all, individuals and therefore must be suppressed by any means possible to preserve the collective.
2. The tribe of the people of the gun are outsiders to the tribe of the people of the non-gun. Anything that harms the outsider is good because outsiders are viewed as threats to the tribe.
3. The question assumes facts not in evidence. In particular the question assumes the anti-gun mind is capable of understanding cause and effect. Therefore the question has little or no meaning within the context of the anti-gun tribe advocating restrictions on guns.
4. Because they are incapable of distinguishing action from accomplishment. These are the same people that protest, demonstrate, and chant. Action for the sake of action is their "currency".
5. The leaders of the anti-gun movement know the truth but also know that the majority of people are so philosophical bankrupt they can be persuaded to use the force of government against innocents to further their own agenda.