When your students arrive late in a system that is predicated on the notion of group instruction, where not being present will either result in the student missing critical information, or result in everyone being held back from learning critical information, then it is a problem.

Call it delinquency or whatever you want, but you can't re-imagine the importance of punctuality from within the traditional system. Non-negligible amounts of lateness are bad in that system. There's no sugar-coating it.

If you can structure your teaching so that it doesn't matter who is present when, only that everyone's present for a while at least some of the time, then awesome! You can give a good deal of flexibility. This is better for almost everyone if it can be done, completely independent of views on race!

But if you can't, then holding certain students to standards that will harm them or their classmates, is not a kindness. It just perpetuates and exacerbates already unfortunate disparities in skills and knowledge.

Personally, I think that group instruction is fraught with problems, and I think you're very brave and admirable for taking on the role of educating our children. I wish you the best of luck!