Yep it always sounded like a silly bit of reasoning to me as well (the impact on defenders). These guys see the impact in training every day. They know who is performing and how they are performing. When you are dropped and it's for performance rather than tactical reasons, the players will have zero issues with it whatsoever. This is top level footie. They are used to it, and the best want to play with the best. The clean sheet means as much to the defenders as it does to the goalie, so they want whomever better gives them that assurance behind them, not who is more chummy or writes better player tribune articles.
Towards the end there was that free kick when Everton sent everyone forwards and Pickford launched it into the box. Raya came out, claimed and was fouled. In my mind I was thinking Ramsdale would probably have sat back and let the defenders deal with it or tried to punch instead of catching, and then it becomes a 50-50 situation which could cause trouble at a critical point in the game. That's the kind of subtle difference in goalkeeping approach - taking the initiative and calming things down, keeping everyone comfortable - that wins you games and helps you defuse a potential shaky scenario.
This may not be a good situation for Ramsdale to be in and I sympathize with that, but it's 100% a win for Arsenal.