Where are you seeing this? I read the Arsenal sub reddit a fair bit and they like him and feel sorry for him as Arteta doesnt play to his strengths.
I also just read it on Reddit on the soccer sub Daily Discussion.
Some quotes from Arsenal fans:
‘Literally a back breaking signing. Best way to put it, hes like 38 year old ronaldo at man utd, but he cant jump for crosses cant hold the ball doesnt have a good first touch has no passing ability whatsoever and only gets non pen goals against bottom 5 pl teams. Literally a back breaking signing.’
‘Dude are you guys blind? Every time we try to speed play up and get this guy in channels he loses the ball. Teams are going man for man more and more and we are playing minus 1 player in buildup because he cant keep the ball, win a long ball or run the channel and keep it. He fucking sucks.’
‘The thing is, he's treated like a make a wish kid by his supporters.
"Oh, he puts a shift in"- yeah, that's the bare minimum of his job.
Meanwhile, his touch is consistently dogshit, he goes down every 5 seconds looking for a penalty, he seems unable to hold off defenders, and he can't even link play due to poor technical ability.
At least Merino has the tech to bring guys into play.
My dream scenario is that Berta uses his Atleti ties to orchestrate some kind of Gyok + cash swap for Alvarez this summer, but it's a pipe dream I'm afraid.’
I also listen to a podcast where one of the hosts is an Arsenal fan and he slags him off at every opportunity.