If it really was 14%, it did make a difference. It depends how close overall margins are, but it's reckoned that fewer than a million voters ever make a difference. My vote has never made a difference, which makes a mockery of democracy and there are millions of people in the same situation. I've never voted tactically, because I've never had the opportunity. I vote according to my opinion of the best candidate, just so that when I look at the totals, I can say to myself that the total for X party would have been one less without my vote.
As I wrote before, If I did have an opportunity to make a difference, I would vote to achieve what I would consider to be the best outcome. I would even have voted Conservative in 2015, if I'd lived in South Thanet just to deny Ukip and Farage a seat. If you look at the results and compare them with previous elections, it's clear that thousands of others did vote Conservative rather than their usual party.
I don't suppose anybody thinks Churchill had become a Communist-supporting Stalinist, when the UK fought on the same side as the Soviet Union in WW2. It was about supporting the least bad.