Hi, thanks for finding a way to re-enable Tampermonkey. Once the scripts are exported you can also install Tampermonkey BETA from the Chrome Web Store since it is not blacklisted (at the moment).
I have no idea why Tampermonkey is considered to be malicious. I guess some algorithm wet wild.
I already contacted the review team via my Opera extension developer account. Hopefully they can tell me more about this issue.
Sorry for any inconvenience.