But the OP did not call anyone stupid. And it was Farage that she called racist, not everyone who voted for him
This idea that one should never attack the right wing because that's calling voters 'stupid' and 'looking down on them' and will justify them in voting for the right, is something that the right have put forward to intimidate and silence their opponents.
FWIW, I don't look down on the right wing; I'm terrified of them and their views.
It's true that just saying what's wrong with your opponents is not generally enough to win and may even put people off voting altogether. (Though Trump and his colleagues did pretty well by negative campaigning. It's interesting that the right are very ready to point out the Democrats' failure of calling opponents 'deplorables' but not their own success of calling them 'Crooked Hillary' and 'Sleepy Joe' and 'enemies within' and 'childless cat ladies'., etc., etc,)
What is needed is more positive policies. Labour are losing support through their continued Tory-lite - and not always even all that lite- austerity policies. And I speak as someone who opposed Corbyn and preferred Starmer's caution and moderation, but it's going too far.
There's no point in trying to win the support of ideological hard-right-wingers. The left and centr need policies that will attract current non-voters, and those who are tempted to vote Reform just to 'get a change'.
Perhaps we need to look outside Europe and the USA to the recent successes, rather against the odds, of left-of-centre parties in Canada and Australia. What lessons might their successful campaigns teach Labour and other non-right-wing parties here?