The idea of recruiting more and more random men sounded stupid at first, but when one thought about it thoroughly, it was nothing but smart! The village needed an extra life of ground-defenses, or more exactly, Tutan needed them.
In order to deal with these threats from space properly, Tutan had to survive, and surely was the most important member of this newly refurbished, metallic village. They needed plenty of guards near and around the village for the same reason, as they had to pose a unique threat against enemies, one lasers cannot replicate.
Plenty of these guards could die, yes, but that was a part of the trade, and everyone would be well-informed about it. Tutan didn't care to preserve their lives, and had only felt guilty towards the people from this single village of rhinos until now, and built them a new home because they were the victims of an alien attack.