in secular governments with a majority of Muslim adherents, they tend to look the other way when they persecute a minority (unless the persecution is so blatant and gratuitous that the government is forced to do something).
Let's not generelize. 'Confederate States of America' during the civil war period, was defenitely not a nation with a majority of Muslim adherents, but for sure a minority group was enslaved and persecuted there. We could even say in the south up until the civil rights era of the 60's and 70's the minorities were persecuted and the government was looking the other way.
I think it has more to do with the education, exposure and overally economic well being of the citizens. As the education level, economic / living conditions of parts of the world get somewhere close to America or Western Europe, acceptance of minorities will be better.