Because the stakes are so low.
Climate skeptics have violated UK law by breaking into an email server and publishing a load of correspondence full of scientific slang (a "trick" is the scientist's equivalent of a computer engineer's "hack": an elegant (or inelegant) solution to a gnarly problem), personal vindictiveness and childish photoshopping.
Nothing they've released invalidates the scientific truth of global warming.
RealClimate.org, another intended target of the hackers, said it best:
Yes, folks, climate skeptics have stooped to breaking the law and violating the privacy of personal communications to warn us that...scientists are human.
Since emails are normally intended to be private, people writing them are, shall we say, somewhat freer in expressing themselves than they would in a public statement. For instance, we are sure it comes as no shock to know that many scientists do not hold Steve McIntyre in high regard. Nor that a large group of them thought that the Soon and Baliunas (2003), Douglass et al (2008) or McClean et al (2009) papers were not very good (to say the least) and should not have been published. These sentiments have been made abundantly clear in the literature (though possibly less bluntly).
More interesting is what is not contained in the emails. There is no evidence of any worldwide conspiracy, no mention of George Soros nefariously funding climate research, no grand plan to ‘get rid of the MWP’, no admission that global warming is a hoax, no evidence of the falsifying of data, and no ‘marching orders’ from our socialist/communist/vegetarian overlords. The truly paranoid will put this down to the hackers also being in on the plot though.