Why do people say that Machida fighting style is boring and a p*ssy way to fight?

Because as you watch the fight he is generally moving away from his opponents as striking only when he knows he will land. If you want to see non-stop action, you won't get it. If you want to see someone use true martial arts watch Machida. He has the lowest percentage of getting hit in the UFC because he is so elusive. He also has the second highest percentage of strikes landed, first is his training partner Anderson Silva. There is nothing weak about the way he fights. He fights extremely smart. The one time he tried to be more aggressive it cost him, Shogun knocked him out.