I don't know what C. Ronaldo, had deep down in his mind for making the comment, but despite seeing reasons from his perspective I don't entirely agree with him. Some analysts are suggesting that he made those comments because of Messi, being his rival but we wouldn't know for sure. Selecting ballon d'Or winner from players that have won a UEFA champions league is not fair because there are many great players that have not been opportuned to win the trophy. I don't know the whole criteria for selecting perticipants for the best player but giving much focus on champions league trophy is not a good criteria.
I don't understand how Messi being Ronaldo's rival has anything to do with his comments. Because Messi is his rival doesn't mean he has anything against the 17 years old kid Yamal, but sincerely speaking during the times of Ronaldo the award organizers judge based on Trophies won by an individual an not by the personal performance of players that's why even Messi won the award easily after winning the World Cup and then sometimes later they started favouring players based on performance and not trophies won so I think the organizers are the ones making everything difficult. Winning a major competition like the World Cup and Champions league and also winning domestic trophies should definitely give a player more chances of winning the award.
Winning trophies are very vital because let's take for example Cole Palmer that plays in the conference league performs so well and has more goals involvement than any player through out the season should be given the award without winning any major trophy? It's not right so winning the champions league and other trophies plays an important part too.
I think the organizers are the ones been bias and not making everything clear.