But you are. The game will throw a tutorial how to build a FOB at some point at you and you can't cancel it. You have to build a FOB. Unless you stay totally offline I guess.You are not forced to build an FOB.
This is stupid advice. When you make it to the end you get 10 soldiers from the whole pool of the player (Direct Contracts nonwhitstanding of course). Put your best soldiers on defense so the enemy won't get to the end. Make them pay with BLOOD.Don't set high rank FOB defense, leave at E-D also putting contracts on soldiers makes them unavailable for FOB defense.