Jeremy Corbyn for example is actually a decent human being (can vouch for this as work with him a bit in Westminster), despite some of his policies. However he is hounded out by the media and political class.
Mandatory reselection after boundary changes should see to that.
Corbyn catches flak because despite loudly proclaiming how straight talking and honest and pure he is, he refuses to disavow Marx (rather: dodged a question asking him to in a classic politician style), and praised Fidel Castro, both men whose ideas and policies caused profound suffering on a massive scale. That rather implies that if Corbyn ever got anywhere near actual power he'd rapidly start abusing it.