People need not complain because Ronaldo's exclusion from the match because it would have made no or little difference. Manchester City was in total control of the match until the last ten minutes. The pace of the match was very fast and I doubt if Ronaldo would have kept up the pace considering his age. The loss can be very frustrating considering that United have had straight four wins but I am sure they would bounce back. I heard coach Erik ten Hag has called for a meeting with the players for them to analyze what went wrong. United needs to solve its midfield and defensive problems because they really underperformed.
If there is no result, and 6-3 from their principled neighbors from Manchester is a terrible result, then it is not surprising that people complain about the absence of this or that player who, in their opinion, could strengthen the game. Maybe you are right about the fact that Ronaldo would not have coped with the pace of the match, but I think it is useless to speculate about what did not happen, and ten Hag did not give Ronaldo a chance to prove himself in this match. I also think it is a suicidal step for the current Manchester United to try to compete with a club like Manchester City at the pace of the match and we need to look for other ways to achieve an acceptable result, including with the participation of Ronaldo. As it is, I feel that the wall of mutual misunderstanding between the head coach and the player will only grow, because it is difficult to show your best qualities when you are physically prevented from doing so.