The term "dis" is slang for "disrespect" so dissing and not having respect for something is one and the same.
In any case, I don't know where you got the notion that because Metheny expects the music to evolve and move forward that he is somehow disrespecting Miles or Coltrane (two of the most progressive and forward thinking musicians of the genre). Both began in bebop but then pushed the music into different places, instead of just staying within the confines of bebop. In other words, they moved forward, just like Metheny said.
If the music becomes stagnant, it will die.