I gotta wonder if the Dominion ever bothered naming their vessels, or if they just gave them their equivilent of an alpha-numeric designation code.
I play as a Human captain, spaceborne, but descended from North Americans. I noticed it is an American habit to give current or former enemy planes/ships/etc some silly or less than flattering names. NATO designations for fighter jets are an example of this (Fishbed, Flanker, etc) or old Japanese planes (Zeke, Zero, Judy, Betty, etc).
Hence Bedbug. It's not flattering. It kinda makes fun of the fact that it's an enemy vessel, and the name still sticks out.
And face it... it kinda looks like a Bedbug.
As for Jem'Hadar... who knows. They probably don't care to name anything less than a capital ship. They're rather practical, down to earth bunch. Probably see ship names as superfluous. Treat them more like fighter squad designations.. but that's just a guess.
You fill in the blanks. Cryptic looked like they were getting a hold on things but the last 7 days shows they want our money with a massive profit, not just a good profit, someone wants to milk this game for the next project.