I was wondering why S.O. doesnt have Designated Marksman listed as a position. It's different from a sniper because a DM is an integral part of the squad, while a sniper in usually alone.

try not to get all caught up in the "positions" Play the way you want, and have fun. If you want to call yourself a designated marksman, go for it.
The only reason companies make positions is to sell more products.
EDIT: Welcome to the forums!!!

Most folks here lump snipers, ghost flanker & marksman into the same category anyway.

Ok, sweet.

You can also say that DM is a role performed by somebody in a particular "position" and doesn't constitute a position in and of itself.

I say that the DM can't be a position that one person can play. In the sport of paintball the object is to MARK out your opponent. So if you assign one person as the designated marksman, they are the only people who can get kills! Yeah, I'm blowing it out of proportion, but it's best just to play for the sake of playing! don't get caught up in positions.

The only difference between DM and sniper is the need for stealth. While both can use stealth its required for the sniper.