The opposition does not have the votes to defeat the government with political purity.
You are going to need Tory votes.
You will need votes from people on the right. And they WILL NOT and they DO NOT share your politics. But . . . okay? . . . BUT
YOU. NEED. THEIR. FUCKING. VOTES.
So if Tories have got reason to vote against the government, just take the fucking votes and shut your damn bitching about the purity of their motives.