I’d argue that let’s play commentary is a review of the game. Now maybe not machinima using in-game footage, but let’s plays that actually comment on the game are in effect doing some sort of review.
To the OP: you really don’t have any reason not to contest it, in my opinion. If you fail, it’s not going to get worse. But, yeah, your claim would be fair use, not that you own the content. You don’t, anymore than a fanfic writer owns their content.