Google Docs follows the same standards as Microsoft Docs when it comes to comments in documentation; they are ephemeral only to ask/provide clarification on a paragraph/sentence.
After which the highlighted portion should be corrected and the comment removed when all collaborators have agreed on the change. In Microsoft, this will be done with deleting the comment.
Google Docs provide a semi-state where you can mark the comment as resolved
So that when you export to .doc, the comment markup will not appear there.
As shown above the first comment is not there because it was marked as resolved in Google Docs, so it makes no sense to deal with the comment again (this based on the assumption that by resolving the comment, one has resolved the issue in that comment).
Another way to do it, would be to create a copy which will not carry across the comments.