You'd probably be best served in a country with proportional representation, because in a FPTP system ideological purity means electoral failure. FPTP parties need to be broad churches as they have to appeal to a wide range of people because the electoral system limits realistic choice.
And who exactly does years of perpetual Tory rule help while Labour flounces off so you can vote your conscience without any caveats?
btw the last Labour government despite my long list of grievances with it, did a hell of a lot of good. A hell of a lot more than Corbyn will ever get the chance to do.
The FPTP system is flawed, and that is a huge problem.
Moving to the right is not an option for a lot of people. Supporting somebody they believe in, and getting their vote counted is important to those people. They feel good about their vote. They actually want to vote instead of voting for somebody they hate. What is wrong with that? Are you suggesting that people should ignore the leader they want and vote for somebody they hate just because the flawed system makes it hard for them?
Blair's government also done some unforgivable things, and in many ways set the blueprint for Cameron. Blair's government introduced some absolutely unforgivable policies. Many of the problems that are still around today are Blair's fault. The current social housing crisis is Blair's fault. The current welfare system that treats almost all claimants as lazy benefit cheats is Blair's fault. Disabled people being treated like absolute dirt is Blair's fault. Cameron's government wasn't even far off from Blair's when we are talking about the treatment of the most vulnerable. Welfare cuts would have especially been a big thing for New Labour if they were allowed to carry on.