I don't think this is a slippery slope towards text modification.

Note that there are already problems with emoji being different across platforms. Here is a short article from the GroupLens people at the University of Minnesota: http://grouplens.org/blog/investigating-the-potential-for-mi...

I'm not a huge fan of Apple's general "safe" content approach either despite being an Apple user, but to me this is a tiny and insignificant political statement relative to all the issues they have with the app store/iTunes content and Beats 1 censorship.