Looking at the link in the OP, it's hard to consider this whole business as reasonable or about empowering parents to guide their children. The language is explicit in its extreme tone, and also in its expressed goal of influencing public policy. Sure, it's not itself a government site, but it is aimed straight at government and makes no bones about it.
Of course this is not really a site aimed at freedom of speech, but at the limitation of choice, and the incitement to action. Anyone who is even the robotic similacrum of a parent does not send a child to a mystery event without knowing what it is. No children are protected here from the content of shows. They, and all other children, are protected from their existence.
If, contrary to the opinion voiced above, the point of this site is to incite action against venues, then if the posting of false locations results in the wrong places being picketed, harassed, bombed, or whatever, then good. The organization deserves it.
If this is just a site where opinion is to be voiced, no harm is done anyway. If you're going to be a convincing poster, you're going to have to indulge in anti-drag rhetoric similar to that of the site's developers, and as Poe's law suggests, if done well it will simply swell the apparent numbers of protestors, and the site's stated goal of influencing public policy will be helped.
e.t.a. in response to Warp12's post above, "Maybe I don't want my young children around ...etc." ...then don't send them! It's been a long time since my kids were little, but I still remember how it was done. My kids were pretty free and their upbringing (not surprisingly, eh?) pretty liberal, but I knew where they were going and what they were doing. They weren't ******* feral!