If a Jew comes late to class (in college, etc.), is it a Chillul Hashem? I’m not saying that it is good to be late – of course not – but is it really such a grave sin as to be a Chillul Hashem and not even YK atones? If he is running late, would it be better not to come at all than to walk in with a yarmulke and tzitzis and a long beard ten minutes late and make a Chillul Hashem?
An act is considered a chillul Hashem if it is below the standard expected from such a person. (The bigger the person the greater the expectation) Regarding your situation, it will depend on what is the norm in the collage, if people do come late occasionally, and it isn’t looked down upon, then it isn’t a chillul Hashem, but of it is then yes. I don’t know your situation, but if walking into class with a yarmulka, tzitzis and a beard, will lower the people in the class’s opinion of orthodox people, then it will be a chillul Hashem. Another point to consider is that if the people in the class already know you, and you usually don’t come late, and act nicely to them, if you come late one time, and it isn’t considered rude to walk in late when it is a one time occurance, then it would also be alright. Again all depending on the situation