He is removing that independence. By granting himself powers to fire the IG without involving other people, it will not matter whether the IG is hired through a vigourous vetting exercise. He can just fire him any time. That will in turn force the IG to take instructions from him or face the sack.
Uhuru was drunk when the people expressed their views to Ghai and others about the new constitution. That the people did not want the IG hired and fired by the President alone is something Uhuru never heard. He was absent from the scene. That people do not want an imperial president who rules like King is something unheard of. He just looks at the new constitution as having taken away his father's wonderful powers.
He will be taught the lesson that Moi learned. After he shoots 40, 60 100 people dead and still more coming to die, will he probably understand why people died for these changes.
Sounds like Museveni's govt. Are police independent?