129+ people are dead, murdered. A further 300+ are critically injured. There are a few things to be said about this:
(1) Obviously, this is a tragedy. The victims and their families have my deepest condolences.
(2) Some people have been politicising the tragedy, some have been getting annoyed at people politicising it, some have been saying that it is inherently political and that to resist politicisation is to accept that it will happen again.
This third group is of course right, but that doesn't mean we should politicise it immediately. If we can avoid attacks on people between death and burial (empirically, of course, most people can't - but at least we have that rule, and it's one that I hold myself to) then I don't see why we can't allow a similar grace period after events like this.
Furthermore, immediate reactions are knee-jerk reactions. Until we know more about the attackers than "They were Syrian and ISIS is claiming responsibility," everyone who considers this evidence for their viewpoint is guilty of updating based upon fictional evidence.
(3) There are fears that this will lead to reduced freedoms in France and in the Western world generally due to heightened security. I hope these fears turn out to be wrong, though I suspect that they probably will be.
The French government has sealed the border. We would do well to recall the words of the Marquis de Condorcet, who wrote (something along the lines of) "All moral principles admit of exceptions, and laws that are usually unjust may be required in certain emergencies. The injustice occurs when these laws are permitted to continue beyond the emergency." There are exceptions to any presumption of liberty, and they are probably much more frequent than Caplan and Huemer would like to believe.
(4) 129 deaths is, in the grand scheme of things, not many (See Brienne Yudkowsky; I endorse the sentiment, if not necessarily the tone. Around 100 people die each day in traffic accidents in the US alone.) If maintaining liberal society meant sacrificing 130 people every day, I would do it in a heartbeat.
Of course, "liberal society" is not a single package. One is free to say that, without some restrictions on freedom for security's sake, there would be vastly more than 130 extra deaths every day. We could, one might claim, implement this extra security without leading to bigger government in any other domains. Both claims are, in my view, fanciful. Most people are basically alright, and there are not enough people evil or misguided enough to sustain that rate of terrorism. Moreover, the tendency is in most cases for government power to be abused.
In addition, more powers for security agencies are useless unless these powers are actually used.
(5) I'm sympathetic to Muslims who see anti-immigration and anti-Islamic statements and feel the need to respond before a superweapon develops. They have a partial pass on politicisation.
(6) The most obvious political statements to be made about the attack are (a) allowing immigration does indeed have dangers, and (b) Obama was incorrect when he claimed that "No [non-US] country has a problem with shootings" and blamed gun ownership. As someone who is very pro-immigration and who leans pro-gun but sees it as a relatively unimportant issue, my reluctance to have the issue politicised may of course be because the politicisation is inconvenient for me. This might also be related to why I'm downplaying the significance of the attacks. We are all biased, and Russ Roberts is right to say that we should admit our biases (though I think he is perhaps too resigned to this fact, and ought to put more effort into being less biased).