I will choose to listen to the MFG. They describe the line as a 50/50 Copolymer. You can call it what you like.
Mono is a generic term used in fishing, Mono means single, technically FC is a monofilament line.
It takes monomers to create polymers and the word poly means many - Not two as you used incorrectly in your original post, much the same way you incorrectly stated that copolymer lines were created from two monofilaments.
There a literally thousands of different monomers, line mfg's choose blends of monomers to create copolymer lines with the specific characteristics that they want.
You seem like a knowledgeable guy, you just misstated some of your original post.