What I don't understand about this is how people are able to express their dissatisfaction about someone else making the code faster, when it's so transparent t

What I don't understand about this is how people are able to express their dissatisfaction about someone else making the code faster, when it's so transparent that they are just butt hurt that their way of doing it wasn't so good after all. Of course I get that such people could from then on hold a silent grudge against you, but I can't understand how they can openly complain about this without making it totally obvious that it's just an ego thing.