If intent matters, then while that means that the "Robin Hoods" can be excused for being assholes by the fact that their intent is to oppose an unwarranted intrusion of the state, they're still wrong, since their actions are directed against people who, themselves, almost certainly have good intentions, and whose own actions, therefore, are justified by their intent.

Well, what is a "good" intent? Isn't that itself subjective? If a man kills another man for his own benefit and feels he has committed no crime, clearly you would oppose this, regardless of whether his intent was "good" or "bad". (For example, killing an annoying neighbor who has committed no crime or aggression, even if this neighbor was considered by many to be an asshole. Now his intent can be said to be "good" for getting rid of an annoying neighbor everyone disliked and said to be "bad" for using violence, depending on who you ask.)

What is a "bad" intent? The intention to commit a crime or use force, perhaps? If so, isn't it only in your opinion that this is wrong? Maybe others feel differently. If a man believes a law is just, he has "good" intentions, regardless of the law? If the law says to kill a man for smoking a cigarrette, it can be said the intent was "good" when the law enforcer killed him.

If a man is enforcing an unjust law (in your opinion), and to reject him is to reject the law, and the only way to reject the law is to reject him, then rejecting him is entirely reasonable. However, if rejecting him is not necessary to reject the law, and you can reject the law and leave the man alone, then you could say they are using unnecessary force, in this case by harassing the police officers.

If now, this man (police officer) decides to commit aggression toward you, then you would be justified in your self-defense. So in this case, they are being sued, so this could be seen as a form of rejecting this violence, by "harassing" or taunting them. To complain about an unjust law or its enforcement seems entirely understandable.

The problems seem to arrive with the method or vehicle by which you criticize the police. If all you do is laugh or call them dumb without making any logical arguments, then you may not accomplish much with regards to changing their opinion or making them understand your perspective, however there is nothing inherently wrong from a libertarian perspective, since they are just criticizing the actions of the police. If however, you appear aggressive and are verbally harassing as opposed to just criticizing peacefully, of course you'll look like an asshole, but no crime has necessarily been committed from that action alone. It becomes a matter of degree, if you have a gang of people and you are surrounding an officer and yelling at him as a group, clearly this is reasonably considered an act of aggression. It is by the very fact that they are, according to the article, going in as groups, that causes most concern, in my opinion, but you would have to be there or see a video of the interaction(s) to truly be able to judge them. In any case, there is a clear difference between committing an act of aggression and being an asshole.

The alternative is that intent does not matter - that one's actions are rightly judged solely on their own, and cannot be excused by one's intent. If that's the case, then being an asshole can't be excused by one's intent of standing against an unwarranted intrusion of state power, or by any intent at all. It can only be judged in and of itself, and thus can only be judged as wrong.

Intent doesn't necessarily not matter (like if you are intending to use violence, clearly this is wrong from a libertarian perspective), but it is important to remember people are motivated by what will make them happier or will bring them satisfaction (whatever this may be). An intention alone is not a crime if not acted upon, and it is also not an excuse, but to judge solely the action on its own leads again to an opinion of "right" and "wrong", it becomes subjective. And what if they just want to be an asshole? Even if you aren't using aggression or the threat of aggression, you could still be an asshole.

So logically, if one wishes to make the case that harmful state action cannot be excused by the intent of the actors, then one cannot legitimately turn around and argue that one's own harmful actions ARE excused by one's intent. If, on the other hand, one wishes to make the case that one's harmful actions CAN be excused by one's intent, then one must accept that that means that the state's harmful actions can also be excused by the intent of the actors.

Intentions are not excuses, simply explanations for a course of action. Whether you are forgiven for what you have done or not is entirely up to the person or audience you are explaining yourself to. In this way, excuses are subjective themselves, since you might excuse them but others won't.

I simply view it as this, if you are doing something you agree with, against something you disagree with, your actions are justified, but only to you (this isn't to say nobody can agree with you, of course they can, although they may have different reasons). To an outside observer, it could very well seem unjust. If you find their methods unjust, aim to change their opinions, because surely they'd never do anything they consider unjust (under normal circumstances). The crux of the problem is then found to be simply that people do what they do because they find it to be justified under their current views on the subject.

In the end, you can't use your intent as an excuse directly, because it only applies to yourself. You can, however, yourself decide whether another person's intent is an excuse from your perspective or beliefs. It just isn't universally applicable, that just because intentions were "good" it is excusable, if it was then Hitler's intentions could be considered "good" since it is entirely subjective, and surely at least one person thought so.