I hear both sides. While I am fairly certain that this will ultimately have a negative effect on the kids that were there, I understand that this protest was never intended to be for their benefit but rather to protest against public chilul shabbos. Is that a fair trade-off?
I did speak with a rabbi who I consider to be one of the world's foremost experts on helping OTD kids (and I have personal experience with way too many of them), and he was vehemently against it. He felt that a protest like this will cause significantly more kids to go off, as it now created an us-vs-them mentality that until now only simmered below the surface but is now being forced on them.
12 years ago I was ordered to leave Lakewood because of a (in hindsight) very trivial incident. Do you know what that type of ostracization does to an angry teenager? It makes them angrier and more eager to do the things that caused them to be ostracized in the first place. Some of these kids may have been only testing the waters, hanging out with friends who are much more brazen than them right now. Now they feel like they there's no return. Some of these kids have friends that they will now convince to join them who otherwise were only being mechalel shabbos behind closed doors. There are plenty of kids who are currently in yeshiva and looking the part, but also engaging in all forms of illicit activities including drugs and chilul shabbos. Many of these kids will now feel emboldened to join a "community" of like minded kids. Etc etc etc.
Chop off the limb to save the body, I get that concept even if I don't agree with it. But what about anything connected to that limb? This has consequences reaching far beyond the kids that were physically being mechalel shabbos at the lake, and I don't think anyone thought about this beyond how it would affect the protesters and the protestees.
My 2 cents.