Margaret Thatcher fiercely supported a "Yes" vote for remaining in the Common Market in 1975. Tony Benn, Jeremy Corbyn, Audrey Wise, Dennis Skinner and most right thinking members of the left campaigned for a "no" vote to a rich man's club that they believed threatened democracy and destroyed jobs in the UK.
The modern left seems either to characterises Brexit supporting Labour supporters as racist homophobes or ignorant simpletons who, unable to identify their own interests best, are led by the nose by malign populists with simple solutions. I don't know anyone from Hartlepool at all and it is, I suppose, possible that either or both propositions are true, but repeatedly telling them so and then asking them to vote for you, I would have thought unlikely to produce positive results.
Labour's likely policies under Kier Starmer continue to be unknown, Owen Jones writes rather well about this in the Guardian.
The Tories get a more or less free pass on large scale corruption in the allocation of contracts and attention is focused on bashing the ebullient Boris and fretting about when he opted to pay for refurbishing the Downing Street flat rather than allowing Tory donors so to do.
To add insult to insult, the local party was given a long list of one candidate, who was known to continue his robust opposition to Brexit.
You don't have to forgive the Jim Crow laws or hate Lincoln, a Republican, to vote Democrat nor I suspect, do you need to forgive Thatcher to vote Tory, do you?