I haven't played the DLC and I don't think I will for a long, long time but "this is too difficult" seems like a fair review of the Shadow of the Erdtree DLC. I've seen multiple experts on FromSoft games who have been fans for decades and played every game multiple times say that Elden Ring's base-game difficulty steers to hard at times, pidgeonholing people into only playing certain classes or builds to have a chance so it seems like it's important for the DLC to fix the, at times, unfair nature of the game. If it doesn't for some people that's a legitamate flaw.
I don't think games journalists are entirely in the right but at least criticize the way they talk about difficulty, not the fact they mentioned difficulty at all. Like, I think the word "difficulty for difficulty's sake" is a cliche that isn't very descriptive and shouldn't be used anymore... so criticize that instead of just the fact they called it difficult. Also enough with the highlighting one sentence of a review and saying that's the only reason the game scored bad according to them.