Raid matchmaking would hurt absolutely nobody, Yes there is Lfg and second party apps to make teams but they are not new player friendly and usually ask for x amount of clears or must have certain weapons. Having matchmaking available for raids would at the very least let people try the different encounters hence giving them more experience to try and join an lfg team. And as already stated how in anyway would it affect people that have already completed raids or have a solid team matchmaking would be optional if you don't like it don't use it.