First, Why do you think that Apple claims a trademark on the codepoint? It's not something Apple mentioned in the quote I did earlier:
> The graphic image associated with the Apple logo character is not authorized for use without permission of Apple, and unauthorized use might constitute trademark infringement.
I also did a USPTO trademark search for 'F8FF' and found nothing, so it doesn't look like the codepoint is trademarked.
Second, even if there were some sort of trademark on F8FF, inclusion of a symbol in a font isn't in and of itself trademark infringement. The use must cause a likelihood of customer confusion, otherwise no infringement is possible.
Take a look at http://fortawesome.github.io/Font-Awesome/icons/#brand or http://www.brandsoftheworld.com/search/logo?search_api_views... and tell me if you think they had to permission from the trademark holders.
Use of a trademark doesn't mean trademark infringement. Codhisattva's comment is not trademark infringement. There's no misrepresentation or market confusion. I can say things like "compatible with Micosoft Windows" even though I don't control that trademark or have permission from Microsoft.
Not only that, but in the US Codhisattva's comment is covered by free speech. I can sell a button that says "No !" as a form of protest or political commentary even if selling a T-shirt which says "I♥!" is likely infringement (doubly so if it infringes on NYC's INY style).