Sorry not time to read the whole thread, but am dismayed that this should have happened to OP's DD who seems brave and brilliant to have found her independent thoughts and confident enough to articulate them.
Unfortunately for her she's has no had the lesson that adults aren't always right, and that some adults can take advantage of position of power to try and make others think like them.
Quite simply if young people are being asked to say who inspires them the adults in charge should have made it clear everyone is entitled to their own opinions.
So firstly the pupils who tried to shout her down failed in their roles as they should have challenged their behaviour. We are mean to be a democratic country, not one run by mob rule.
Secondly there is no way that whoever was running the day should have moved her nominating JKR to the hate board. Teachers are not supposed to imposed their views on pupils in their care.
And yes if this was funded by the local authority she should complain about being bullied by a teacher. Or at least tell the school.
But appreciate she may not want to do anything public.
There was a video that quite a few on FWR shared a link to where a teached in the US challenged a student who said JKR was unacceptable. If anyone has the link (I will search) can you add it as OP's DD might enjoy it because it shows how easily people are duped into being mental sheep, but also there is no evidence the was JKH says or stands for is hate speech.
Best wishes to both of you.