Here I have to kindly disagree though. I think their Discovery-review were not well researched, but very fair overall. They just don't care this much for DIS. Which is not that surprising, a running theme of them through the last years has been the overabundance of badly made genre crap to cash in on popular IPs. Even MARVEL-movies, which they generally like, get that criticism, and DIS comes much better off than what they say about DC, Star Wars or a wole lot of other "nerd" IPs.
As for their "Last Jedi"-review, while I didn't agree with them on everything, I think they made some very good points about the movies weird tonal shifts. Which really helped me to understand why I didn't like this movie (even though I thought it was better than all the other Disney Star Wars movies): The simply fact that in the end, everybody was dying, decimated, only the fewest lucky survivors who had all their friends die around them - and they were cracking JOKES all the time(!) and had calm discussions in the background (instead of being scared and shell-shocked to their bones) - was probably the thing that disturbed me so much.
Thing is: Redlettermedia became famous by crapping on pop-culture (Star Wars) and doing horrible rape-jokes during that. They turned down the rape-jokes. But they're still doing the thing they're famous for: Crapping on everything popular. But they do so in a very entertaining and insightfull manner, that's why I keep watching them. You just have to expect that - if they're reviewing something well-known that you like - they gonna' crap on it.
And overall - wile they couldn't have made clearer they don't really care about DIS - I think the Trek shorts got away much better than most stuff on RLM.