Since when is thinking about something a crime??? It is the act that is important.
47,000 people are on it. Most of them have not committed any crime... Probably. We don't actually know, because if you're on it, the government won't tell you why - or even that you're on it.
A criminal conspiracy is more than thinking about a crime, but a lot less than actually committing the act.
Would stopping mass shootings and not-called-terorrism-but-domestic-terror be part of the use cases here? Like if you were to ignore some other laws and track gun ownership and purchases, maybe cross reference it with the use/prescription of certain medications and then cross reference that with anti-social posts on the internet or associations with certain call-themselve-patriots-but-really-hate-the-government type groups you might stop some mass shootings. Maybe save some actual lives.
It's a terrible rabbit hole to go down, we need to stop it all ASAP.
E.g. "we now have technology that can prevent rapes of children before they even happen. So many children today live in the direct neighborhood of a potential rapist - and no-one could do anything because nobody knew. But now we can spot and remove the potential rapists and give the children back the pieceful and carefree life that they deserve.
Unfortunately, as of now, making use of the technology would be in violation of certain laws - laws that made a lot of sense in the last century. But given the changes in society and the urgency of the matter, we feel a reformulation would be more than justified..."
The courts of the US have literally always that freedom of speech is not unlimited.
You can argue for a compelling state interest in increasing the term of punishment for a violent offender based on his opinions about race. But (1) it's hard to argue the state interest in longer prison terms and (2) it's really hard to prove hate, so there's an easy due process appeal here.
In our current hyper sensitive culture there's a lot of expectations that people think a certain way.