You have been on extended maternity leave and on your return, with hair against your company's uniform standards, you contemplate that they may be institutionally racist?
Good luck with that, but remember the rest of us on this forum who work in uniform have to abide by our respective standards, so are unlikely to be sympathetic.
I suggest you comb out your dreadlocks and have a think about your priorities, ie your new-born. Once again, good luck.