Finally. This is my kind of conversation.
I do agree that in most cases, when someone believes A is justified while B is not, there is at least a little bit of inherent bias. However, as Nachtel may have pointed out, it's not very fair to be comparing any two things to each other, as A could be justified for a reason that, if used for B, wouldn't make any sense.
For example, let's say there's no law indicated you must stay off of quiet, secluded neighbourhood roads.
If you are jaywalking on a secluded arterial road, you could argue that it's legal, and that would be justified since residents of the area have as much right to these quiet roads as vehicles do, there's not much risk or harm that can come from simply crossing that road, and frankly there's not really a better alternative when you consider the distance to the crosswalk, the time it takes to get there, and the amount of risk you're mitigating.
On the other hand, let's say you are sitting down, cross-legged, right in the middle of that same road. You could argue that it's legal—and you'd be right, because there's no law set in place telling you to stay off that road—but logically you can understand that this argument isn't enough to validate the action. In other words, it's still wrong. He's sitting right in the middle of the road. There's danger of injury from the cars wanting to pass through every several minutes; there's danger of infection from cuts they could get from the uneven paving; and it's just a stupid thing to be doing, no matter how you look at it. Sure, it's legal, but context matters. You're not quickly crossing the road, you're meditating in the middle of it. These are two very different contexts that require very different explanations as to why you think they're justified.
I understand the point you're trying to make—and I agree with that point, for the most part; if you want to back up what you're doing, you need to be open-minded and ready to accept others that are doing different things for the same reason. But there's a context to everything that we as humans do, and that context couldn't be more important in situations like these.
(Also this may not have been the most relevant example, but it was the first one to come to mind. Let me know if this example doesn't really make sense with what you're talking about)