In the end I would say he made the comparison too early as we dont have enough information for either. What an a-hole.
It's like you took the words right out of my mouth. Also, I read the article front to back and it's hard to say that this person reads OPM, and doesn't read AC seriously in the first place. This can easily be seen by the way they discredit Saitama as being dumb (probably from failing the hero written exam so shamefully. It only makes it worse when we don't know how much of it was a educational exam or a morality exam.) They also arbitrarily add in feats for powers for Korosensei that are indescribable (He destroyed 70% of the moon, but we have no idea how, nor how he'll destroy the planet.)
Also, weaknesses:
Not as fast as some other fighters? (citation needed)
punches can be dodged by someone faster than him (isn't that a weakness for literally every character ever created ever?)
Yet, he doesn't even list the actual weaknesses for Saitama:
Weak to special sale days
Ultra self-conscience about being bald
Worries about not standing out
Hero names
Money
Prone to breaking things (like King's games)
Consequences
Really, really, really self-conscience about being bald
Loose sense of morality
Also, the fight/ synopsis was kinda... uneducated. Korosensei doesn't make clones, he just moves really fast to create shadow clones (Saitama can do the same thing.) Correct me if I'm wrong on this as well, but Korosensei moves around at high speeds using air foils and special lubrication to not be impeded by air friction (So he doesn't really fly either, he just jumps the same as Saitama in a sense. Therefore, he would have the exact same -no flying- problem in space or otherwise)
It upsets me, but it's mainly the fact that this person discredits both of these characters to this extent that's the most upsetting to me.