In all seriousness to the OP: it’s people with really, really dreadful senses of humor being “wacky” and “random.”
Hate to rain on the parade and all, you’re good folk, really…but god damn that stuff annoys me. Obviously, I could have avoided clicking the thread, but I was hoping for a kindred spirit who would be railing against the evils of trite “randomness” as it pertains to nefarious stock characters.
Well, there was a movie called Robot Ninja, which has to be the coolest title ever. I can’t recall any robot pirates off-hand, unless you count Charles Dance’s character in Space Truckers, but he was really more of a cyborg pirate, with a pull-start for his dick. But I digress.
I don’t think it’s random or trite. I think it’s an important philosophical debate which is key to understanding the cornerstones on which Western society is constructed. 
I mean, pirates and ninjas are pretty much philosophical opposites.
Pirates like flashy clothes and big shiny earrings. Ninjas like black, unobtrusive clothing.
Pirates have big, loud blasty things. Ninjas have small, silent, pointy things.
Pirates have animal sidekicks. Ninjas are self-reliant.
Pirates work for material reward and a good rocking party! Ninjas work for, I don’t know, loyalty to their sensei.
To me, pirates win because they have the most fun pillaging and plundering. They sing their nonsensical pirate songs (which are all about women, boats, and drinking, of course) and dance crazy peg-leg jigs. And drink! Dude, they’re so perenially drunk that they think digging a big hole and putting all their money in it is a good idea! What the fuck, pirates, you’re so drunk!
To you, ninjas may win because they’re more “effective” and “don’t fall over all the time.” Pfft. Whatever, ninjas. Whatever.
Of course, when you try to combine the two, havoc ensues. See: Surf Ninjas.
Conjugate the verb “to ninje”:
I ninje
She ninjes
We are ninjeing
You have ninjen
And, ergo “He is a ninja”.
No, ninjas live on secret ninja mountains. Mountains>water. Besides, ninjas are allied with hippos which can swim out and chew holes in the pirates’ ships.
It is actually not random at all and I mean that in all seriousness. It is a type of parody humor but randomness never enters into it. If you spend any time around 4 - 10 year old boys you will see that variations on this really do exist IRL. When I was that age, we argued about what the Incredible Hulk would be able to do or what Bo and Luke Duke could pull off in the General Lee. Each age group has their own version. Even so called “normal” adults have lesser versions of these arguments with sports teams. That is where the humor lies.
I just bought the Real Ultimate Power book from Barnes and Noble last night. It roughly mirrors the website but is much darker. It tells the story of a young boy with ADHD and a terrible home life that finds an escapist fantasy in Ninjas. He becomes obsessed with them and ascribes all kinds of supernatural capabilities to them but combines them with revenge fanatasies on the world. Like so much great literature, it flies right over the heads of plebians but contains a profound message at the core.
–Roberts, B. 1709. Problems and paradoxes in contemporary Ninja Studies. J. Pir. Sci. 49:202-228.
The Pittsburgh Pirates have Four World Championships (1925, 1960, 1971, 1979), Nine Pennants (1901-1903, 1909, 1925, 1927, 1960, 1971, 1979), Nine division titles (1970-1972, 1974-1975, 1979, 1990-1992), and 14 Post-Season Appearances (1903, 1909, 1925, 1927, 1960, 1970-1972, 1974-1975, 1979, 1990-1992). They also have a stadium where you can drink beer. Ninjas don’t even have a ball team.
The oddmakers won’t allow it. It would be impossible to bet having infinity to one odds on every game. Also, the fans would hate simply rooting for their team to just avoid dying rather than having a chance to actually win the game.
Pirates win. Is there an official Talk Like A Ninja Day? I don’t think so.
Is there a Ninja-themed ride in any amusement park anywhere in the world? No? I guess that’s coz pirates are way cooler and nobody would enjoy a “hide in the shadows like a small, frightened animal” ride anyway.
Nobody knows what ninjas talk like. The only people who hear ninjas speak are either other ninjas or dead, with the possible overlap of dead ninjas. People who try to talk like ninjas just end up doing bad Bruce Lee / Mr. Miyagi impressions.
And yes, there is at least one ninja-themed rollercoaster.
Other than teh name, what is ninjaesque about it? Nothing. Nothing to differentiate it from teh Loch NessMonster. Pirates pimpslap ninjas. That is the way of the world.
No, the reason that there are no ninja theme-parks and few rides is that they would be too intense for most people and would cause people to crap their pants. That doesn’t sell. Kiddy themes like pirates go over much better in a family friendly environment. That is a huge argument AGAINST pirate domination. I can’t believe I even have to explain this stuff.
Ninjitsu is the “art of invisibility”–i.e. the art of hiding.
And what are ninjas hiding from?
ARRRR! 
What he said. With knobs on it.
Ninjas vs. pirates? As in… Donatello vs. Feathersword?
The ninjas win.
To put the argument on a firmer footing:
Pirate boots versus ninja boots – the pirates win majorly for coolness versus dorkiness.