Aren't emojis pictograms and ideograms but not usually logograms? They're direct depictions of concepts, not usually direct stand-ins for words like logograms are.
Better examples of logograms in English I think are &, $, %, @,+,=, etc. We actually have a bunch we use all the time.
Specifically they said 'Kanji', though, so I think they're talking more about the actual character structure of :.|:;.
It's a reference to an entry in the webcomic series Ctrl+Alt+Del. The female lead has suffered a miscarriage, and this particular entry in the comic, titled Loss, depicts her boyfriend's journey through the hospital, entering the front door alone, talking to the receptionist, talking to the doctor, then standing at her bedside.
Ctrl+Alt+Del competes (competed?) with Penny Arcade, it's normally a lighthearted junk food entertainment kind of webcomic aimed at a gamer audience, that SUDDENLY slammed into very heavy material, and then SUDDENLY slammed back out of it. The comic became very widely mocked for the tone whiplash, and one notable form of mockery was making increasingly minimalistic representations of it, often with a "you just lost the game" kind of intention, ie how minimalistic can you go while still reminding others of the comic. A common depiction might be I Ii II I_ (one man standing, a man standing and a woman sitting, so she's shorter, two men standing at equal height, and then a man standing and a woman lying down) but now :.|:; is even more condensed while maintaining the four panel arrangement.
This is a meme from 2008; it's been going around awhile. So to those who have been long familiar with the meme that graphic kind of works like a hieroglyph or kanji character; it's a very simplified depiction of something that carries a sound/concept. You kind of read it as the word "Loss."
Well, no. It wouldn't be the first kanji of English. Kanji is the Japanese pronunciation of 漢字 (hanzi), where 漢 means han/China and 字 means character/letter. Ergo, it makes no sense to call it "the English language's first and only Chinese character."
If you need to use a Japanese word to describe this, then 絵文字 (e mo ji; picture, character/symbol) fits better, but we already have several words for that, like pictogram or pictograph. One could argue that smileys fall into this category as well. So perhaps it's a smiley.
Learning random cool stuff like this is part of why I like lemmy, and why I used to like reddit. Please don't shut down constructive contributions with low effort snark. And before you use your line on me, if I were fun at parties, I would get off lemmy and go to parties.