In a better-written series, everything Washio is going through/doing would've hit better.
I mean, he spent a good part of being a hero (or whatever) building up that lab only to discover he was being used and, ultimately, destroyed that lab and escaped with the monstergirls.
He sees himself as a failure for not noticing it sooner and buries that memory under a ton of trauma.
He keeps trying to not remember that part of his life because it wasn't great, and only snaps into action when he finds out the jackass at the school he teaches at was the scientist behind the experiments at the lab he destroyed.
Like, that right there is a fine setup, nothing wrong with that. But, man, it just doesn't land when our antagonist is Shadow the Edgehog over here.