In this report about a schoolboy being punished for allegedly making the Nazi salute to his teacher, there are two aspects of the school's response that strike me as being questionable - though I don't pretend to know the full facts of the case.
First, making a Nazi salute, though obviously aimed against the teacher's authority, is not in all contexts racist. Done knowingly in the presence of Jews and as a provocation of or act of contempt towards them, it would be anti-Semitic and therefore racist. But in other contexts, it might rather suggest that the person towards whom it is directed is behaving in dictatorial fashion; and there is nothing racist about that suggestion, though in most cases it would be an overstatement and so quite possibly offend.
Second, the head teacher of the school is reported to have said: 'A racist incident is defined by perception of other people rather than the intention of the person who committed it and this is the point we tried to make.' I think this is also no good. Racist incidents are, indeed, not just a matter of what is intended, as I have argued many times on this blog. But neither is the 'perception of other people' an adequate criterion. If it were, anyone could claim any word or gesture to be racist and that would settle the issue of whether it was. You could not have a flimsy or unfounded accusation of racism. There has to be some basis in the history and symbolism of the particular racism being alleged - whether anti-black, anti-Jewish, anti-Romani, anti-Chinese, or whatever - linking the incident or utterance in question with that 'tradition' of racial prejudice and persecution.