Because Bill Clinton sent them their because Somali’s were “starving” and we had to feed them or some such.
Although Clinton screwed it up (refusing C130 gunships, etc.), it is my understanding that GHW Bush sent our troops to Somalia for some goofball mission about feeding the locals - well, watching the well fed locals march through the streets gleefully carrying the body parts of American pilots they slaughtered made me feel just great that we fed the pigs. And I wondered why Jeb and Neil ad GW weren’t there on the front line.