That's not surprising when you consider that the strikers were sacrificing everything for a cause that others (whether the strikebreakers or the police) were prepared to crush for their own ends. It's akin to being on different sides in a civil war, and it doesn't surprise me that feelings run deep. People lost houses, jobs, marriages and even liberty in cases which are only now being overturned. It wasn't just a difference of opinion.
It's very sad when it runs to the next generations though. I can understand it in some ways, but not in others. These things do. I suppose it's similar to hatreds between people from places who were on different sides in wars, or people whose countries were invaded, even hundreds of years ago. Nobody alive can remember what happened, and nobody alive could possibly have been responsible, but it's a folk memory.
Not quite the same thing, but I remember going on holiday to Brittany with friends when I was about 19. The locals often asked if we were German before talking to us (we'd attempted to speak French - clearly not very well
). When they heard that we were British their attitude changed immediately, and they couldn't be more helpful.
We were all born around 1960, so couldn't have taken any part in the war on either side, but given what the people had gone through they were in no mood to be nice to Germans. Sad, but understandable.