The emoji "" can't be normalized further -- it's a "" followed by a "". If you just split on code points rather than grapheme clusters, even after normalizing, your naïve truncation algorithm will have accidentally changed the skin colors of emoji. Or turned the flag of Norway into an "". Or turned the rainbow flag into a white flag .
EDIT: oh lord Hacker News strips emoji. You get the idea even though HN ruined the illustrations. Not my fault HN is broken.
Whether the absence of emojis on HN is a feature or a bug is arguable. But if you can't figure out a way to work around this constraint (e.g. put your example literally anywhere else on the web and post a link here) HN is probably not a good fit for you.
Reading a discussion thread where each message is just a link to some pastebin with the actual message isn't very nice. Besides, I wasn't going to write the message again after HN removed arbitrary parts of it, hence the edit; I think people got the gist. You may feel that discussion about Unicode doesn't belong on HN but I feel otherwise.
Reading discussion threads full of silly emojis isn't "very nice" either, at least for a certain kind of audience. It's a tradeoff, and the powers that be at HN have decided to optimize for sober discussion over expressivity. It's a defensible decision. Keeping HN from degenerating into Reddit is already hard enough.
EDIT: oh lord Hacker News strips emoji. You get the idea even though HN ruined the illustrations. Not my fault HN is broken.