You're right, but I think they were making a different point in the title than that the pressure of war would lead to unwise decisions (though they may have been going for both at once).

They were also pointing out that the internet is likely to do more good than harm as far as de-escalating tensions goes, if you want to end a war, then turning off the internet is probably not a good policy, since it closes off an opportunity for dialogue and shared perspectives, so could do more harm than any potential good caused by the economic/social pressure.

So "[As a sanction during] Wartime is a Bad Time to Mess with the Internet [if the eventual intent is to de-escalate the war]" is a more reasonable interpretation of the title.