Parent Categories are not necessary when adding categories to a new page. For example:
Lieutenant already has the Henchmen category, therefore it doesn't need Villains which is a parent cat. The same with Arkham City; the page doesn't also need it as it is a parent category to Arkham City Characters which would be the one we would use.
Honestly, you're perfectly fine and have been doing a good job. The categories are an extreme mess here and I have been (very slowly) trying to get them cleaner and tightened up. Unfortunately it's going to take a while to get everything fixed properly, so I don't fault you at all especially when using pages I haven't attended to yet.
I know there are a lot of them that still need work. I was doing a lot of them for a bit, but it became overwhelming to the point that I just started doing them on pages I came across, that had recent edits, etc.
I've been monitoring your daily edits, and it seems that 46 of your last 50 edits have been to your user page. That's 92% of your recent activity. For the last few months, your main contribution each day you only make a slight change to your user page with the last two edits being something you added yesterday and then took off today. I have also noticed this behavior of yours persists on other wiki sites.
This kind of activity is suspect and reads very heavily of badge-hunting which is frowned upon at this wiki. I have come across this activity by other editors doing this on other sites I admin on and have approached them and taken steps to correct this. I would ask that you either contribute in some other way than adding a small change to your user page, or if you seem to need to add so much to your user page that you do it in one large edit.
I do appreciate that someone has taken an interest in cleaning up the mess that is the categories on this site. I just didn't want you to think that I was targeting your edits if you see me changing something after you made an edit to it.