A review is not required to commit. The PR itself says "Add more commits by pushing to the bpo-19903 branch on lulouie/cpython." As far as I know, unresolved requests do not block for cpython. The Merge button appears to still be 'alive' after my red review.
I have done reviews on other issues, both + and -, with comments on individual lines. I like it best when there is only a single commit at the time of review. Otherwise, I don't see any way to comment on the total change after multiple unsquashed commits. I also don't like commenting on an obsolete line or searching through multiple commits to find the last that touched a line.
I accepted your invitation over 1/2 hour ago and got confirmation from github. But pushing with this revised command
git push git@github.com:lulouie/cpython pr_1382:bpo-19903
still fails, with the same message.