A lot has been said about Muslim support for the BJP in Uttar Pradesh given the scale of its victory, but none of this is borne out by the numbers. What can we say about how Muslims voted?
1. There is no evidence that Muslims voted for the BJP.
Despite political statements and some stories in the media, there is just no evidence for this. There is not a single constituency where the BJP's voteshare exceeds that of the Hindu population of that constituency.
Sahibabad is the only constituency where it's close--the winning BJP candidate, Sunil Kumar Sharma, won 61% of the votes in the constituency, while the share of Hindu population in the constituency is between 60 and 65%. Data on voteshares and the Hindu and Muslim population come from Datanet India, which compiled the data from the Election Commission of India and the Census of India respectively.
In that constituency, the Congress and BSP candidates between them got 36% of the votes; the Muslim population of that constituency is between 35 and 40%.
2. BJP candidates winning from a large number of seats with a significant Muslim population does not mean that Muslims voted for the BJP.
In a first-past-the-post system, candidates typically need between 30-35% of the voteshare in a constituency to win. In this election, BJP candidates did particularly well; the median voteshare of winning BJP candidates was a whopping 43.64%.
Yet what most forget is that even in UP, there are few Muslim-majority constituencies. There are only seven constituencies in UP with more than 50% Muslims (meaning that a party can win the state without a single Muslim vote)--and the Samajwadi Party won all of these. The BJP's winning streak essentially begins when the Muslim population goes below 45%.
3. Strategic voting failed
Of 82 constituencies with more than 30% Muslims, the BJP won 62. But it appears that the Muslim vote was split between the SP and the BSP--in 60 of these constituencies, their combined voteshare was higher than that of the Muslim population. Given that in a majority of these constituencies both or one of the SP/ INC and BSP had a Muslim candidate, it is very likely that the Muslim vote got split between the SP and the BSP.
So rather than strategically voting to keep the BJP out, it could be argued that UP's Muslims actually failed at strategic voting.