Not sure why we can't just hold off on judging how true someone is to their espoused beliefs by waiting to see what fruit comes from their life. Like this is a fun one around here, what has come from Trump? Doesn't that speak a lot about what he really believes and what he stands for? If you spout hate, and division, and dissension, usually in your wake will be hate, division, and dissension.
People have claimed a religion, secularism in China for example, amongst a multitude of things to get what they want who knows, what's going on in Kanye's head (if anything). I don't know Kanye West or anything about him.
Should we just assume that all people no matter their world view, or espoused world views are simply using it for what they get out of it? It's probably a fair assumption.
However, you can usually tell by the trail a person leaves behind how closely they hold their values, morals, world-views because they will eventually leave a trail that speaks much louder than their words ever will. It's fair to say, "I question if this dude is sincere", it's also fair to say, "We'll know when it's done how sincere he was".