Please don’t say that satmar is “misusing” the 3 shavuos. It is 100% a machlokes haposkim, and who are we to decide the halacha? everyone agrees that the Satmar Ruv z”l was a goan. If you don’t want to pakin like him, becasue you have your poskim, that’s fine. But it is a very valid shita in halacha (I won’t even get into that most ashkenzic poskim actually held this before the creation of the state).
Just like you don’t want satmar yidden to say that your shita has no mekor, don’t say it about the satmar shita (which again is not only satmar. It’s only that the Satmar Ruv wrote a few seforim on the subject)
NK is a sperate matter entirely, as they are the ONLY ones in klal Yiroel who will protest together with our enemies. No legitimate gadol biYisroel held that you can do that, so they “misusing” the satmar shita in that way.