I have the same question.
A possible workaround is to open the Element inspection panel on your browser (press F12 if you use Firefox) -> Click the Inspect icon on the top left corner of the panel (or Ctrl+Shift+C) -> hover your mouse over the comment you want to copy, click it -> in the inspection panel html code, expand the text element, double click it, and copy.

https://community.qualtrics.com/XMcommunity/discussion/comment/41038#Comment_41038That's what I ended up doing