I don’t really read/watch outside news sources so I did not know anything about the frum angle of this story until I read it here. All I can really add is that I think you are wrong about some of the chillul Hashem comments in regard to their attendance. I am under the impression a chillul Hashem would involve non Jews, or those far removed, seeing a frum Jew doing something like this. The problem you may not realize is that many if not most would have no idea that half the avairos you all have so kindly tallied are even improper. Growing up as a more modern Jew, I had many friends who attended lectures/conferences on Shabbos by pre paying and not writing etc. and I never knew it was wrong until much later in life. If you told me this family used to be secular and they have made so many changes in their lives in order to keep shabbos, or that they had a more limited religious education to the best of their knowledge, I would be only impressed. I don’t want to discuss or know where they are holding. If they hand me a check I can research it myself, but so much of what they are accused of violating is not things many of the public would be noticing. And it may very well end up being lashon hora, pure and simple.
And for those who insist we need to show our love for Hashem by speaking out against it’s transgressors, first look thru your own backyard. We have many baal habatim and gvirim who are making money from businesses that feed basar v cholov to Jews, and other things who are honored and respected and their money is in many of your pockets.
Does this negate the actions of the above? No. But you are either fighting for shabbos, or you aren’t. And if you are fighting for shabbos, then don’t pick and choose which transgressors you find more offensive or public to make your case.