To be fair, regarding your analysis at the end of 3x2, Tanjiro did say during the training session montage that the kid was a total amateur. He didn't really understand what he was talking about, so his comment about Tanjiro being bad and not knowing the basics should be taken with a grain of salt. His goal was just to get Tanjiro to get good against the doll.
Also, Tokito is a jerk in this episode, and I'm not going to defend him. Specifically within the context of him being so much stronger than Tanjiro, it was mentioned by Tengen in a monologue that Tokito is a prodigy and became a Hashira just months after entering the corps. With that being said, Tengen did not count himself among the strongest of the Hashira, so the show still has places to go with showing us their power.