Just guessing - but I think that you might find that, being CITY fans, for a lot of those that will be voting Conservative in the forthcoming election, or did in 2015, there might be a common development process, along the lines of:
1. They were born into staunch Labour voting families and areas (Eccles for me)
2. Were 'indoctrinated' that you only vote one way - Labour - without thought or question
3. And that was what we did as soon as we/they were of voting age, but then
4. We/they grew up and developed the ability to think for themselves and to be able to analyse offerings from each party and make judgements
5. Given that the Labour party had, during the same period, become arrogant and took their core vote for granted - these 'free-thinking' people were able to judge Labour's policies and the personalities that were leading them and find them wanting
It is democracy at work.