In "Tooba-Achooba!", the titular illness renders Totobory's leaves unusable. The Tooba-Achooba weed can essentially paralyze him.
Even worse; what might happen should Rosygury ever find out about that?
Borys and gurys can never become bad or good, respectively. If a bory were to commit something heinous like murder, they would still be considered good. Meanwhile, a gury could save a life and they would still be considered evil. That's a bit scary to think about.
Totobory tends to judge if things are good or not based on taste. What might happen should he come across something toxic that just happens to taste good?