The symbols you wanted to include are in the Dingbats and Miscellaneous Symbols blocks, which I expect are all banned because they contain some emoji and this was the cheap way to be rid of those, quick test: "" "", that's a Miscellaneous Symbol and a Dingbat of no emotional valence to speak of and certainly not colourful ones.

As you can see, that's the deal: they're casualties. I wouldn't mind a more discerning filter, but then again, I wouldn't mind a dark mode, and here it is, years later.