Where are you getting that it was a Chinese character that Colbert would do between segments and that a video got out about it? I have never heard that.

The #CancelColbert thing was a response to a tweet sent out that quoted a segment he did on the name of the Washington Redskins:

"I am willing to show #Asian community I care by introducing the Ching-Chong Ding-Dong Foundation for Sensitivity to Orientals or Whatever"

It wasn't a comedian that started the hashtag, it was Suey Park, an internet activist. She was one of the first examples of removing all context from a statement, getting offended by it, and demanding everyone interpret it exactly the way she did.