Because you just said your purpose was to pursuade people. It’s entirely possible many people you meet will not share your same moral construct. It’s even more probable that they just won’t be appealed to on moral grounds. Even if they do share the same beliefs about what “should and shouldn’t” be done to people, many times they feel like appeal to morality is appeal to religion. And it turns them off. And even more often than that, appealing to morals is almost completely useless becase you’re talking to people who already hold contradicting (or at least logically inconsistant) beliefs to begin with.
Just because you might get someone to admit that taking money from people without their permission is wrong, even if you promise to do good things with it, doesn’t mean that they’ll have some huge epiphany when you point out that that’s exactly what taxation is. Just watch Jan Helfeld’s interviews and you’ll see person after person after person either say “well that’s different”, or (believe it or not) try to claim taxes are voluntary.
Statists are statists because it’s all they know. And you’re literally talking about questioning the entire social construct which they’ve lived their entire life by. That is not an easy thing for people. If something has always been there, people have an incredibly hard time imagining it not being there…To a point at which they question how the world would even function otherwise.
Moral arguments are useful and important, but many times they are not the slightest bit effective. And again, you just said your whole point was convincing people. So, if you’ll forgive me, it doesn’t really matter what you think is irrelevant or what matters. To go on as if your reason for agreeing with libertarian principles is the only valid reason, and that people not only have to agree with you, but they have to do so in the way you think they should is just asinine and quite arrogant.
I could not give a shit if someone follows NAP because they think a flying spaghetti monster told them to and they feel like it’s a good idea to do what he says. So long as they abide by those principles, it makes no difference to me. And I do not see why it should make a difference to you. Is it really not enough that people become ancap? They have to do so for the reasons you want them to? They have to reach those conclusions in the way you think is most relevant or logical? The whole point is what works to help other people see the light. And for most people, they’re ultimate wants are the same as ours and everyone else’s: better living conditions for everyone, more prosperity, more abundance, less hunger, less violence, more peace, et cetera. And if you can demonstrate to them that those ends are not achieved through the methods advanced through “conventional wisdom”, and that you reach much more favorable outcomes through freedom, it can be very appealing and convincing.
It is much easier to get someone to agree that one thing works better than another when they can see the results. It is much more difficult to convince someone that their entire moral outlook is inconsistant and confused.