This Argument Might Prove the Opposite of What Was Intended
I'm sure many of my fellow anti-authoritarian crackpots have come across this speculation on what might have happened if King George III's government could have used traffic analysis. There is a minor problem with it: Back then, governments could really have used traffic analysis.
In the Good Old Days, communications were done using these strange devices called letters and post offices. Post offices, in turn, were usually run by the government. (Anybody who tried bypassing the postal monopoly would be in a pile of trouble.) That monopoly meant that, although the government wasn't permitted to open the letters (and if you believe that…), it could definitely find out who was communicating with whom.
In short, the current controversy is not about some new tyranny but about reviving an old one. That doesn't make it good (especially when you consider the lengths the government went to to try to keep it secret), but we should keep matters in perspective.
Meanwhile, it might make more sense to emphasize that the statist arguments can be used by anti-statists as well. For example, “If you try keeping secrets you must have something to hide…” can apply to the government as well.