I think all the Laws have two components to them, and each one consists of these components in a different ratio. There is:
(a) "does doing this corrupt you in some way, twisting your brain or making you see it as the way to solve all your problems?"
and
(b) "is doing this a really bad idea for everyone?"
It's worth noting that (a) needn't always twist you metaphysically, as long as it encourages a dependency on doing that thing again (represented by a reduction in your ability to resist compels on your aspects by reducing your Refresh). And (b) is more of a "legal" rather than "metaphysical" issue.
I think all the Laws have (b) in them to some degree, but not all of them explicitly have (a) in every instance.
Killing, mind reading, domination, transforming and necromancy all incorporate (a) for sure, I'd say. They are all about Doing Bad Things to other people, even if that was not the intention - although this "intention" thing is a can of squirmy worms, as we are all well aware.
We don't know enough about the time travel one as we haven't seen it used much (only the once, really) - but it could incorporate the "dependency" aspect of (a) while the potential for world-destroying paradox definitely brings in (b) much more.
As for the Outer Gates... I suspect you can have (a) AND/OR (b) here. This is because you could be a nasty guy wanting power and reaching out to the worst possible entities for it, which is corrupting in itself but the Outsiders are probably all about corruption as well - which is (a). But you could be a good guy, not yet tempted by the power they offer but foolishly researching them in order to fight them. This is clearly a Bad Idea (b) and should not be encouraged to avoid the risk of researchers being influenced by the Nasties, yet the 'perpetrator' may not be a bad person at all. In this instance I believe it is possible for someone to research the Outer Gates and Outsiders without getting the Lawbreaker stunt and yet still be tried and executed for breaking the Seventh Law.
The Gatekeeper must be a special case of some kind or surely he would be a raving, power-mad lunatic by now. Either he resists or is perhaps immune to their corrupting influence and has special power over them by dint of knowledge or the circumstances of his birth... just like Harry....?