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 :.|:;.