I valued He-man less when She-ra came along.
He-man always had to strain himself when he performed feats of strength. She-ra always lifted objects effortlessly, so it seemed like she was actually physically stronger than He-man.
And She-ra already had a better sword and all these extra powers (eg. healing, talking to animals, sidekick that could fly, better transformation sequence, etc.).
He-man had nothing over She-ra. So, to me, He-man became a nobody, nothing. He had become depreciated, deflated in my mind. I didn't respect him as much anymore. He was less of a hero to me because I always felt bad and embarrassed that She-ra was better than He-man
She-ra fans would always say she is more powerful than He-man and I had no comeback; I had nothing to say because in my heart I knew this was true and it made me feel small and sad and less proud to be a He-man fan.