Theft is never acceptable, no. There is an objective and logical reason as to why this is. Morality simply is the concept of actions we - meaning people - should or should not commit to. Morality does not apply to nature, simply meaning that in which sits outside of the frame of those with personhood - it only applies to people.

So the question becomes, how do we know which actions we should or should not commit to? Well, you can answer this logically, and quite simply, actually.

You already understand that you never want anyone else to violate your will. It is in fact logically impossible to desire the violation of your own will because that in which you will is what you want. If you say one minute that you don't want me to punch you in the face but then the next minute you're OK with it, it is not that your will is such that you wish it to be violated, it is that your will has changed.

And since it is not objectively possible to place the subjective in a structure of hierarchy without that hierarchy being utterly arbitrary, you cannot set value to will. For example, say there is a diamond and both of us desire exclusive authority over it. I cannot make any claims of my desire over this diamond that objectively supersede your desires. Thus, there is no way for us to mandate who deserves the diamond as predicated solely on our feelings.

That being said, because you understand that it would never be permissible to you that I violate your will, it can never be permissible for you to violate mine. So at this juncture all we need to set is the logical standards for how a system of human conflict must work.

Think of it like this - I'll set up a thought experiment example:

You are the only human being on earth and are walking through the woods. You find a diamond on the ground and pick it up. Immediately your will is to hold exclusive authority over that diamond. You want to be the one who decides what happens to it and you would be upset if the diamond became lost, damaged, or otherwise out of your control.

Who has ownership over that diamond? Well, you do. Not because anyone said so, but because it is the only possible outcome in this scenario. You desire exclusive authority over it and there is no other human will of which to contest your will. Those are actually the two logical criteria for ownership. Anything else is just referring to some level of authoritarian justification to mandate that your desires supersede the desires of another. Basically, arbitration through might.

Now imagine I pop into the world and see you with that diamond and I also manifest a will desiring exclusive authority over it. Now how would I obtain my will? Well, I would need to violate your will, which preexists mine. This is actually the logical order of operations of which manifests the idea of theft, mind you. If you had passed by that diamond without a second thought and it wouldn't bother you one bit had I come along later and coveted it as my own, then you never desired ownership and thus, did not hold ownership over the diamond in the first place and as such, I did not need to do anything to another will in order to make mine manifest.

This is why you can own something and gift it, sell it, trade it, or discard it, and the next person to hold ownership over it obtained it through moral means. Keep in mind that it is impossible to own that in which you've stolen just as it is impossible to steal that in which you already own. The constructs of ownership and theft require one another for the other to exist as ideas. If you can own something you've stolen then the very ideas of ownership and theft become arbitrary, and now we're arguing semantics, not ideas.

I can take something from you (like taxes, let's say), and tell you that isn't theft because I have a uniform on, wear a badge, have some kind of formal sounding title, or because I tell you it's legitimate, but none of that renders the act either legitimate nor moral. Taxation is theft not because I say so, but because the cardinal essence (see Aristotle) of the idea itself mandates it.

It does not matter if you're starving to death for instance and you steal food from me, even if I have so much food that I could feed the both of us for 1,000 years, the act of stealing the food itself is an act of theft and every act of theft is objectively immoral because it is logically so. You would never suffer another to violate your will as it pertained to any of your possessions either, including but not limited to food.

What you are likely doing is misconstruing your personal, subjective views of morality. You are allowed to FEEL that someone with food for both of us for 1,000 years who won't give some to a starving person is a bad person, and there's nothing intrinsically wrong with that. I would agree with you on that front (though there may be exceptions, such as say, someone asking for you food who already tried to murder you or your family.)

But personal feelings do not mean it is morally correct to rob them. The logic of that sentiment is extremely nefarious and can be used to mandate literally anything, because it's wholly arbitrary. To use the funny, silly, and stereotypical example of Hitler here, if Hitler decided that the Jews all needed to be destroyed, he is using a similar argument of emotion without logic. He is mandating that his personal, emotional, arbitrary views hold more value than the will of those he means to slaughter because he believes himself to hold greater wisdom then his victims, which is not objectively true.

There is no such thing as the wiser man or the lesser will. To even say that you are entitled to my food for example because you are starving is to stipulate that life itself holds a level of value that is absolute, and it doesn't. A man for example can value anything over the value of life, and all of us actually already do this. If given the choice that a random stranger die, or your child, who would you choose? Let's make the situation even simpler, what if it were a child rapist's life, or your child? So you already agree that life itself has arbitrary value.

With what respect might be owed to you as a stranger on the internet my estimate is you've never thought high enough level about any of this as you're still at a low-level of thinking which is predicated principally on emotion. I do not mean offense in saying that, mind, but you might want to take a step back and think your positions through carefully first.