Why is Prof. Oak such a horrible person to Blue?

Just finished Fire Red, and Professor Oak’s behavior towards Blue (Or Green in this) was concerning as hell. I know from the anime he seems to be a good guy but when Red beats Blue the dude shows up and straight up says “You’re the second best? Pathetic, you’re a horrible trainer who doesn’t love his Pokemon. I’m disappointed in you.” and then he takes Red and walks off leaving Blue staring at the wall.

This was even crazier because the only reason I was able to beat Blue what by spamming hyper potions and using my Haunter with the Destiny Bond move to kamekaze itself for my win. And the guy says BLUE doesn’t love his Pokemon while RED DOES?

I mean he’s a literal 10 year old child who just lost the most important battle of his life, like bro.