Why do some people get so worked up, trying to find loopholes or flaws in the Zero Aggression Principle?
I believe it's because they view it as a threat.
I see it as a promise.
What I mean by that is I don't go around trying to catch people initiating force. What I do is promise people that this is how I will behave toward them. I will not initiate force, nor violate their private property. If I do, I accept the consequences.
It is also a warning of sorts: "This is my line in the sand; as long as you don't cross it, we won't have a problem. If you do, this is what you can expect of me". I don't see that as a threat, but maybe you do.
Most people I notice trying to weasel around the ZAP, while treating it as a threat, are wanting to feel good about reserving some imaginary right to initiate force or violate property. A person who has no aggressive designs doesn't generally think twice about it (other than as a philosophical exercise).
.