As you said yourself, some people will try and pin all of the team's failings on one player. That has been the case with De Gea, Ronaldo, Pogba, Maguire, Rashford etc. It's nothing new and the toxicity directed at Pogba, Maguire, and Rashford (over the course of their careers, not just this season) in particular has been far worse than anything Ronaldo has received from what I've observed. Regardless, it has happened to basically every player in the post Fergie era so Ronaldo absolutely isn't alone in that.