I belive I have seen the game in question, and there is no clear sign of stalling there if you ask me. You can't really say that someone is holding up the game, based on the first turn in a diplo game. This is one of the issues with such reports thru, they are very subjective. Unlike for example, the chat in that same game, which it is much easier to objectively evaluate. https://www.warzone.com/wiki/Rules#The_Rules
Also, this is the rules, and note how broad  is. You shall be respectful to other players at all times.
Anything you find disrespectful, is something you can report.
EDIT: There might be several games at play here, I only saw one of them.
Edited 4/16/2020 08:56:49