The Japanese striker has been accused of going down too easily by certain quarters after recent incidents involving Hearts defender John Souttar and Livingston's Ayo Obileye, which earned Celtic a last-minute penalty.
Kyogo has scored 14 goals and claimed five assists since arriving from the J-League and Postecoglou launched a strong defence of his summer signing as he blasted his critics.
"Who are these brave people, these warriors, who are accusing people, who are out there?" he asked.
"Kyogo is the size of a jockey. He's playing against guys almost a foot taller than him.
"All these brave warriors on the outside casting aspersions, are they?”
Former Rangers players Barry Ferguson and Alex Rae are among those who have criticised Kyogo for supposed play-acting, while former Premier League referee Keith Hackett suggested the striker should face punishment by the Scottish FA should he continue to 'exaggerate'.
"I haven't read it. I won't read it,” Postecoglou added. “You end up in arguments with ignorant people you'll eventually become one of them so I kind of ignore those kind of narratives as you painted it.
"I think Kyogo has been great for our football club and I think he's been great for Scottish football. I'll be surprised if anyone wouldn't want someone of his character and playing ability in their club or their league.
"Who are all these brave soldiers sitting in their studios or lounge rooms or wherever they are, throwing these narratives across the way?"