It's a difficult topic, of course. Opponents of libertarians are quick to point out that the libertarian agenda leads into quite the dystopia. In particular, on the topic of surveillance, it seems fairly clear that at least the hardcore libertarians (in the direction of anarcho-capitalists and the like) are actually happy with surveillance - as long as it is done by private companies and not by the state.
Now these groups are co-opting or even running this campaign which is ostensibly against mass surveillance. That seems something right out of the libertarian propaganda playbook (for a recent collection of quotes out of this playbook, see here: https://www.nsfwcorp.com/dispatch/lying-to-liberals/).
On the other hand, protesting mass surveillance is still a worthy cause. I am not a USian myself, and I can't really tell where I would land on this issue (support stopwatching.us or not) if I were, but it's an important issue to think about.