well, megaman lore is that robot masters are regular robots that were affected by virus

"McDonalds has sponsored you to make a Hamburger Man."

"How's a hamburger gonna kill Megaman?"

Also most of his Robot Masters are designed by children.

There was actually an episode in the latest Megaman cartoon (Yes, another one) when Guts Man got more powerful the more trash he ate.

We have to remember that Wily is an old man, it must be hard to progress with a master plan when you keep forgetting what exactly it was about. x3

Just remember though. Wily would eventually go on to create Zero; The killiest of all kill-bots (regardless of what flag he wound up fighting under).