This annoys me because it's really stupid to say this.
That's like saying "Oh there's a fire in your house and you forgot your phone? Well put the fire out yourself!", it's not like they know what to do on the spot and even have the equipment.
Unless he knows C or Lua really well that when he makes it he will still be interested then you saying this is really pointless.
Even if he did know C or Lua, you think that he could code it and test it multiple times in a flash? No, because in reality he would most likely not even be interested by the time he makes it.