He has a lot of confidence but also a lot of respect for his opponents. In news articles his words are often taken out of context for click bait giving the impression that he is brash and overconfident while his words were much more nuanced. Unless you are a fan, you typically won't read it but the headlines will stick. For example, while he will say that winning the TdF is his ultimate dream, the press might quote it in a way that gives the impression that he has no doubt he will do it. All of this adds to the general perception and for some riders it turns out net negative (like Remco) and others net possitive (like Pogacar). As a result some are also allowed to say more than others. Tom Pidcock said last year that there is a good chance that he will win the TdF. Apparently he can say that without being ridiculed.
It's interesting you also mention Pidcock as I get the sense that both are something of a gift to journos as they are a bit more blunt and open than most, which is then sometimes twisted by the headline writers or perceived as arrogant by fans of other riders. I saw an interview with Pidcock before the TDF where he said that although he had no chance of winning the GC (it seems British journalists keep asking him about winning, guess they're desperate for their next contender), the first couple of stages might suit him and if he won one it may give him a chance of wearing yellow. This became a headline of "I'm going to win the yellow jersey" which was widely perceived as ridiculous by those who just saw the headline.
I'm glad Remco is around as he certainly makes things more interesting and entertaining, both in his racing style which is often exciting and different to other top riders, and in his interviews. I admit that some of his earlier behaviour grated a bit, but he's definitely grown on me and I'm sure I'm far from the only "non-believer" he's converted. Just want to see more duels with the likes of Pog going forwards.