Because he is saying what they want to hear.
I think that it is hard for many to understand Tory party mindset but there are so many factors at play here, not least the desperation to remain in power. They see Johnson as a vote winner, given his twice success in London.
Bizarrely they deny all the issues he brings with him. This denial I think is characteristic of so much in politics.
Johnson firmly announced last week or maybe the week before that he was for leaving without a deal if necessary on 31st. He even seemed to agree at one stage about proroguing.
He has rolled back on all of it since. There has even been suggestions that he is so unreliable/chaotic, that he could just as well choose to revoke.
As for other policies, anybodies guess is as good as anyone else’s.
So in answer to your question.
God knows and even he must be totally bewildered.