That Ghandi image/meme that he posted is from the escapefromreality website. Their whole shtick is a passive-aggressive condemnation of Christians who don't follow hyper grace dogma, like that Ghandi picture communicated. It's baked into hyper grace doctrine. I will admit, though, that I do not see Prince engaging in this kind of passive-aggressive warfare against other Christians. That is to his credit.
What it shows is the foulness that is in the body of Christ that rips apart each other because one thinks differently on an issue. It's un-Christ-like no matter how much we try to mask it or cover it up and this foolish passive-aggressive condemnation nonsense is a perfect example of this.