If the word 'antisemitic' didn't exist, the accusation, phrased in different words, would still carry weight.
I alluded to this already, but it's so rare to hear public figures discuss Israel/Palestine without distorting and filtering what they say to promote one or the other side, it makes resolving things impossible.
A bad bill that weaponises 'antisemitism' is a good reason to oppose the bill's authors and supporters. It is a bad reason to minimise actual cases of antisemitism directed at people who had no involvement with the bill.
What I was driving at is that it's easy for a society, once there are widespread complaints about the weaponisation of some problem to slip into dismissing actual occurrences of the problem.