What oath? They're literally just standing around doing nothing. This deployment is legal, the president is allowed to do it for 30 days. After that you might have some legal fuckery to try and get them there illegally but it's above board for now.

This deployment was legal for up to 30 days. They can only refuse illegal orders

They swore to uphold the Constitution. So far their orders are within the law.

You mean this oath? The one that swears to obey the orders of the president?

“I, ________, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States and of the State of ______ against all enemies, foreign and domestic; that I will bear true faith and allegiance to them; and that I will obey the orders of the President of the United States and the Governor of ______ and the orders of the officers appointed over me, according to law and regulations. So help me God.”