First, and I can’t believe I’m saying this, I think you should be just a tad bit MORE judgemental. Making excuses for people’s bad behavior is a bit like good people doing nothing and allowing evil to take over. You’re passively condoning the activity.
Second, the acceptable amount of littering is zero, not a cigarette butt is ok. I dropped my car off to be repaired and walked to work from there. You know what I saw along my walk. Thousands of cigarette butts. You don’t really see them from a car, but you sure see them on foot.
Third, I’m pretty sure this behavior is just trash humans. There are very few, if any, justifiable reasons not to hang on to your trash until you get to a trash can. This is my humble opinion.