I mainly made the connection because a buddy of mine was making a pirate flag for a party back in college and we were looking for ideas on the internet and found this awesome jolly roger- it was the classic bones-behind-the-head type, but more compact. We thought it looked awesome, so my buddy started working on his flag. I was curious and kept clicking around, and discovered that the graphic came off a skinhead website- we were making an SS flag and didn't even know it!
I'm still 100% pro-pirate flags, but now I warn people so the don't make the same mistake we (almost) made.