And while you’re correct that emojii do require some amount of UTC resources, it’s worth noting that most of that work is done by a special subcommittee to not distract from the mainline work of other languages, and that emojii have brought new attention and new volunteers to TUC - so I’m not sure how significant the impact of adding emojii to their workload really is.
I would summarize the key issues here, but they are complex and I don’t feel qualified to do them justice.
In any case, please see the comments on the HN post (linked by a sibling comment) for that. The issue is in fact wickedly complex, and it’s not clear (even among Bengali speakers) that this is a deficiency in Unicode (vs a deficiency in text entry and rendering software).
We're talking about emoji for crying out loud, the entire idea is frivolous (and that's fine!)
Let's not forget that adding all this complexity to Unicode has a real burden for people who implement Unicode. In practice, the consortium has to prioritize what symbols to support. So, in practice, it's less "embracing all variants of human expression", and more "the ability to communicate in your native language doesn't matter as much as the gender identity of this police emoji".