It’s all a matter of perspective. I don’t think a nutmeg is disrespectful. It will often get the crowd excited and it’s part of what makes the game beautiful.
In America, running up the score is considered disrespectful when the victory is guaranteed. In the NBA, they will often not score deliberately when there’s only time left for one last possession and the game is already settled (and there have been heated confrontations when a player does score in those moments).
Personally, I think it’s more disrespectful to not play to your best abilities against your opponent. If you deliberately take your foot off the gas, you are underestimating them, maybe rightly so but regardless I find that far more disrespectful than getting crushed or nutmegged left and right.
Don’t like Neymar flicking the ball over you at the end of the game? Do something about it without crying or bitching for minutes on end afterward. It’s just very thin-skinned and almost symptomatic of this new generation where we don’t compete and everybody is a winner that we start to see with kids. Sometimes embarrassment is good for you, just like utter losing, that’s where competitive people will find the best sources of motivation.