Pirates or Parenting?

I like to think of myself as a pretty "judge-free" person. We all have our idiosyncrasies that despite my contempt for most of the human race, is one of the things I find fascinating about y'alls species. Tonight however, I found myself treading that fine line between "Am I the asshole here?" And "You gotta let a kid be a kid.".

Allow me to expound.

Buddy has had football practices for a month now and almost all of the 5 year olds on his team have a sibling. One though has a sibling that comes dressed to every practice dressed as a full on pirate. Pantaloons, sword, eye patch, puffy shirt, etc. Now normally I wouldn't bat a lash at a 5 year olds brother dressing as a pirate, but this little Jack Sparrow is 9 years old. NINE. Week one, I thought, "Maybe he's in a play and came straight from school?" but quickly remembered school hadn't started yet. Week 2 I thought, "Well, pantaloons do look pretty testicularly liberating, maybe he knows something we don't!" But by this evening, the writer and the 3 Budweiser's in me couldn't "not ask" when that little bastard child of Penzance showed up in full pirate regalia again, albeit, this time he had obviously sharpied in a mustache and, (wait for it), CHEST PUBES out of the top of his puffy shirt. So I lean in to the dad, and say in my best "I swear I'm not trying to imply your sons an idiot..." voice, I say "Soooo...a pirate huh?". He says "Yep, wears that shit three days a week. To school even. I don't get it, but if I suggest its concernable, my wife gets mad." I quickly turned the subject back to football to avoid the myriad "arrrrrgggh" jokes trying to explode out of my mouth, but it got me thinking, if Buddy was 9 years old and dressing like a pirate to football practice, or publicly and consistently dressing like a pirate, would I nip it, or would I just let it ride? We all know 9 years old is about where concernable bullying starts but is it curbing who our children think they are to save them an ass kicking, or stifling who they want to be out of fear?

Long story short, I like to think I explained child social hierarchy to Buddy growing up to the point that even at 5 he knows pirates are right at the bottom of the food chain, right below the kids that dress like Hobbits. I love individuality, but sooner or later parenting, individuality, and common sense need to have a sit down.
Thoughts?