The point is, there needs to be some law and order in place so that when people abuse this tech to harm people and society and get caught, there's some precedent to stop them and punish them. It doesn't matter if the technology is passive. The intent and action to use it to harm people are not passive and are not analogous to thought crime at all.
There is dire need for regulation with a lot of emerging technologies right now. We're building systems with enormous power which can break human society if misused. I think the intangibility and "passivity" of this tech (or at least how it is perceived) gives us a very false sense of security. Like how a few decades ago very few average people could understand how the internet might have a great impact on society. Obviously they aren't thinking that way anymore.
Check out Charles Stross's speech at C3 about regulatory lag relative to the the accelerated nature of tech growth: https://www.youtube.com/watch?v=RmIgJ64z6Y4