There are many reasons for discriminating against people - sex, religion, race amongst others - that are forbidden by law; there are many others - having a beard, being left-handed - that are not. As you (I presume) well know.So it's ok to discriminate against somebody for any other reason? And surely the hotel were not obligated to give a reason anyway?
In the story which this thread is about, there is no evidence of any illegal discrimination, just an incorrect understanding of the law. Anyone who continues to state or imply that there was such discrimination, without evidence, is dangerously close to stirring up racist feelings. IMHO.