A whip is a finesse weapon. A whip can also be flavoured to being a garotte wire. The pommel of a dagger can be flavoured to be a fist. A light Hammer can be flavoured to be a kick. Stick to the dice and the rules and what you "call" the weapons doesn't matter.
However, there's reasons why the monk text specifically does not mention finesse, but does mention monk weapons can use Dex - unarmed the monk is badass, whereas other Dex builds ain't. Punchy McOrcFace however ain't too bad. Giving a Rogue access to unarmed sneak attack potentially makes him just as badass as a monk in any unarmed, which kinda





on the monks shoes a bit.
Flavour is cool, mechanical there's cause for caution......