That's actually a mistranslation. MEINUNGSFREIHEIT ( capitalized in the original ) means "freedom of expression", or "freedom of speech". I think here it signifies individual freedom of conscience, so he's objecting to the idea of religious hegemony, as advocated by the cited Choudary.
This does not mean he's dismissing Islamic belief. He's saying that Choudary is going too far, and to me it suggests that he had at least been considering "conversion" already at this point.
His post is dated October 25, 2014? A lot could have happened to change his mind in the meantime.