There is 0 difference. None. There's not even a line to cross.

> legally collected data

In both cases, the information is legally collected (or at least, that's the only data we're concerned about in this conversation).

- government using

- individual abusing

^ Both of those are someone in the government using the information. In both cases, someone in the government can use the information in a way that causes an individual great harm; and isn't in the "understood" way the information would be used when it was "pitched" to the public. And in both cases, the person doing it will do what they want an almost certainly face no repercussions if what they're doing is morally, or even legally, wrong.

The government is collecting data (or paying someone else to collect that data, so it's not covered by the rules) and can then use it to cause individuals great harm. That's it, the entire description. The fact that _sometimes_ it's one cop using it to stalk someone or not is irrelevant.