Rules of engagement

1. It is not unreasonable or despicable to, in the wake of a horrific tragedy, demand changes to the law you think will prevent it from happening again.
2. That said, it is unreasonable and despicable to demonize your opponents who have done little but disagree with you, and thus far won the arguments, as responsible for that tragedy.
3. It also doesn't mean you're right.
4. Also the world of politics is a little nuanced. You do not speak for all liberals, or all conservatives.

On the final note:

1. The NRA has itself to blame if an overwhelmingly Democratic government, voted in in 2014, imposes draconian gun control laws. Gun control was a bipartisan issue until you waded in during the mid-nineties and demonized Democrats and liberals, alienating a group that usually sticks up for individual liberties. St Reagan was infamous as Governor of California for getting gun control legislation passed that was aimed at disarming groups he didn't like. The infamous AWB had overwhelming bi-partisan support, attracting the vote of almost every Senator.
2. If you're a liberal (or for that matter a conservative) you need to see through the above. The fact that you can find your political opponents coming up with spectacularly bad arguments for a position you find initially uncomfortable does not make that position wrong. As an example, a liberal might want to actually study the effect of the AWB and its similarity to what's being proposed today. It heavily restricted semi-automatic weapons and crippled magazine sizes. And the studies done do not suggest it made a blind bit of difference when it came to gun crime.

My view?

• There are so many guns of all descriptions in circulation any attempt to limit them will have no affect on availability.
• The difference between an AWB-compliant AR-15 pattern rifle and a standard semi-automatic AR-15 is relatively minor: that is, some psycho who wants the rifle they see on  TV to kill people with (which seems to be the thinking behind banning them) is going to be able to find one, just by modifying a legal rifle.
• I doubt, actually, that America's "gun culture" has much to do with the violence we see. Britain doesn't have a gun culture and there were two major massacres while I lived there. Proportionally to population, the number was much smaller than the US. Proportionally to British gun owners, I'd say the ratio of terrible events to gun owners was much, much, higher. And then there's Switzerland, where there's a semi-automatic version of their military's standard issue assault rifle in many homes, proportionally much larger than here, and there's very little gun crime.
• There are actions that can be taken that would not affect civil liberties, and might help prevent problems, but are treated as beyond the pale by the gun community. Registration is probably the most obvious. Being able to say "We know this person is unsuitable at this moment due to {a relevant mental illness | an injunction after domestic violence | etc }" seems relatively reasonable. A better solution than limiting magazine sizes might be to increase taxes on ammunition not normally used in large quantities by ordinary shooters.
• The other issue people raise is that it's generally felt we don't have an adequate system for identifying people with mental illnesses, with a view that somehow this would have prevented this tragedy. Honestly, I don't know. Lanza is speculated as to having had Asbergers.  Does that normally exhibit itself in a burning need to kill children? Would any treatments for Asbergers  have actually affected whatever it was that caused Lanza to break down?

To be quote honest though, I'm currently of a mind that there just may not be anything that can "be done" after this massacre that would have prevented it from happening, if only it had been done before.