Johnson is a “Politically Correct” Conservative, which means that over time he moves leftward along with the culture (note to people who think it doesn't matter if the culture moves left). The further to the left the culture goes, the more traditional conservatism appears to be “extreme”. Guys like Johnson then try to stay “relevant” by siding with the leftist culture, and they do this by warring (often ferociously) against social conservatives, particularly on cultural issues such as immigration, homosexuality, abortion, etc..
Of course, they insist that they're still conservatives, and offer as “proof” the fact that they want to cut spending, as if spending will ever be cut in a culturally leftist nation.
Johnson was never a conservative. Rather he is a libertine man of the left who consistently hates Islam as much as Christianity and Judaism.