I figure it’s just the same as if someone died from exposure while trying to climb a mountain.

“Searching for Bigfoot” is just a fun interest they had. An excuse to get outside. And they probably got lost or injured or caught unprepared. Happens to tons of people in our country every year.

Now, if they knew they were in danger of dying but decided to press forward in a relentless pursuit of Bigfoot (rather than turn around when they could), then that’d be pretty dumb.