That kind of attitude has always struck me as odd, people would rather vote for the worst case scenario or not vote if the alternative was not a perfect match for them, despite it being far closer to what they'd want.
This is something the left desperately needs to learn from the right, you don't have to hold out for perfect if you can get acceptable now, it is vastly easier to drag things from acceptable towards your ideal if you are the ones in power, as seen by the handmaid's tale playing out in the states these days.
I'll vote for the party/candidate whose policies most reflect my opinions.
But then, I reside in a very safe Labour seat. If I lived in a maginal, there are some lections I'd hold my nose and vote Labour. Wouldn't fill me with pleasure, though, and would be very much a case of 'slightly less shite than the Tories'.
Unfortunately, though, on the majority of core policy*, Labour don't reflect my opinions. Indeed, I think they're far closer to the Tories that they are to me.
* taxation, public spending, privatisation/outsourcing, workers'/union rights, tax-dodging, motorcycles