Because the goal is to force Putin into a negotiation
In order to negotiate what, exactly?
The removal of Assad and the Iranians in return for US support for the Russian naval base. It would be a good deal for Russia, which could stop bleeding lives and rubles and it would be a good deal for the Syrian people who could try to reestablish the democratic government the current Assad president's father overthrew to create his failed dynasty.
The Syrian peoples' Lives are owned by Putin.
Putin makes sure these Syrian people die for his needs and to make money.
Syrian peoples need to either fight or die for their lives.
This is a civil matter between sub-humans in/of the ME Area's etc..
If they want to hire others to fight for them.
Old Blackwater now Academi Erik Lying Traitor Price will kill anythang you want for money.
Betsy DeVos is Erik Prince's sister. She like dead none whitey's as well.