I do believe there was an overt prejudice against bachelors,
but I have not seen the documentary in years. I seem to
remember, that on the assent, into the mountains, a bachelor
was dumped, i.e. abandoned.
My guess: bachelors were less likely to be the owner of a
wagon.

I kind of agree with Susan on the man-thinker and boy-thinker
analysis. Supplementing a man-thinker would almost always be
a (the) woman thinker so they would be thinking ahead on
political power, ownership, supplies etc.

In one film, I remember a member of the group shooting at
a friendly Indian, who was part of the group. Correct me
if I mis-remembered this.

On the other hand, it does not take deep thinking.
A man, seeing his 4-year old daughter on the verge of starvation,
could easily take advantage of a bachelor.
(My view of human nature, I suppose.)

If this group had recently arrived from a Norse culture, where
skiing and sledding was predominant, I think several of the
party would have skied over the pass and got help, early in
the year. A few bachelors would have been perfect for this.

I never understood their fatal Stay-together and Stay-put
philosophy. They really lacked creativity, and a pro-active
approach.