Lew Powell's Frostbitten Feet

[Natty]

There is a passage in the article that irritates me somewhat:

"The fellows will all fight except Yankee Jim and Powell".

Why did Lewis' comrades think he wouldn't fight? Was this because he was so young and they thought him incapable of it? I was always under the impression that Mosby's men were all relatively young fellows..... and he wasn't THAT "green" at the time - the reference to the Dranesville marks his age as almost 20 and makes it clear that Lewis had already been part of Mosby's group for months.
So, why would they assume that Lewis would hold back? Such a big, strong person like him?