Are you a US Citizen? Are you willing to temporarily (temporarily in this case is not implying a short duration, btw) lose your device? Are you able to waste time (as in hours or unlikely but possibly days) at CBP defending your rights without negative repercussions (as in missed flights, possibly missed work, missed family obligations, etc)?

If the answer is yes to all, then sure, politely refuse and stand your ground until you get your way. I try to make sure I can answer all yes when I travel, but the last one isn’t always possible.