Good thoughts but as you point out about Elmo & Zucc, there is no way it stays with just the responsible people. It will also not be limited to protest. Just look at what Florida, Texas, and other states are doing about women's healthcare - any general agent worth its salt and with a bit of data will know about any woman's periods, pregnancies, miscarriages, and travel - which is being criminalized ....
For the national security agencies, I agree. Other than the incoming decapitation assault by the incoming administration who will install leaders based on loyalty to the executive and not competence and loyalty to constitution, most are very honorable.
The vector I worry about is the prosecutorial groups in the states getting hold of the data, either by purchasing it or by subpoena, and pursuing people based on what they find. Even if they only purchase public data, we can be sure some amoral developer will sell them tools to extract from multiple broad data sets info about periods, pregnancy, travel etc.
I'm reminded of the young woman living at home who started receiving postal mail about products for her pregnancy, and she hadn't even told anyone yet, including her parents. These 3rd parties had just inferred it from FB usage data. I'd bet real money that Texas and Florida will be trolling this data hard, and for far more nefarious purposes than merely selling some stuff.
From personal experience in the government contracting world with a TS/SCI clearance, I have a lot of faith in people in charge not letting bad actors abuse these sort of powers.
Less so than before these days, but still Id wager on them holding true to duty to defend the constitution.