For Homero to describe that list of items he stole from the house as "petty" just shows how much he believes he is entitled to take whatever he wants and any complaint can be dismissed as being unwarranted or petty-minded.
It doesn't occur to him that if he owned that house and a tenant had walked off with all those things he wouldn't exactly be passing it off as inconsequential.
The narcissism is strong in this one.
I'm not sure, I think it goes deeper with this one.
Do you recall the reports from the email dump which referred to him tracking his wife's movements? The confused and hurt emails from his wife which alluded to him either having bizarre mood swings or deliberately fucking with her mentally?
He appears to have a weird, nasty controlling streak about him. I don't know enough about the DSM nor am I professionally knowledgeable enough to start tossing out armchair diagnoses on the internet, but a proper psychologist would probably have a field day with him.