Nobody is perfect

Today I got on my five year old about putting our fluffy white cat in the clean clothes hamper while I am folding clothes.  That little guy is special.  I love him with all my heart but he is so stubborn.  He likes to ignore or forget what you tell him.  Which leads to him having to get disciplined.  I usually put him in time out or speak to him sternly.  I tell him "why do you keep putting Luna in the hamper if you know it upsets me."  He tells me "I am sorry."  I respond by pointing out that if he were truly sorry he would not keep repeating the same behaviors that get him in trouble.  His response was "well you're not perfect either."   I was speechless for a minute, I mean really what do you say to that?