I think he genuinely doesn't know who Yoshi is. Anyone with half a brain would know that you can't rip a character, let alone a flagship character, without all sorts of legal and copyright battle.

No one would even risk getting caught. It's bloody Nintendo. They've got a crack team of lawyers just lying in wait to pounce. Low budget indie game or not, who would risk it?

Though I do agree. Must be incredibly rare for someone not to hear of Yoshi. Did he not play Yoshi's Island? Or Super Mario Galaxy II?