Muck ruling

[Frond]

4/8 live LHE game. Guy in the #6 seat calls and puts his 4 chips in the pot but has his cards out in front of him with no chip or anything protecting them like he always has been doing all night. They were in front of him and not too far out away from his stack, kind of a normal spot for most players. Guy on his left in the #7 seat decides to fold and throws his cards in but they both land comingled with # 6's cards. Dealer halts the action and calls the floor over. Tells the floor what happened and the floor rules that both hands are dead and #6 even has to surrender his chips that he called with to the pot. #7 apologized to #6 and gave the guy 4 chips so no problem there. #7 asked the floor if he could whipser his hand to him so that #6 could still play his hand but floor refused. Is this a correct ruling here?

PS. Guy on my left says to me, "Man, I should do what you do and put a chip on your cards on every single hand" I say, "Uh huh"