The protagonist in Daniel Defoe's The Life and Adventures of Robinson Crusoe belongs to the middle class. What was the effect of portraying him as a...

Asis
middle-class, he's expected to make his own way in the world. He wasn't born with a sliver spoon
in his mouth; he hasn't had everything handed to him on a silver platter, as would've been the
case had he been born into the upper-classes. As such, Crusoe has been deeply imbued from an
early age with commercial values and with the overriding necessity of going out into the world
and staking his claim.

It is just such values that motivate Crusoe to engage
in the slave trade. Though still perfectly legal at that time, the slave trade was widely
considered immoral and disreputable, certainly not the kind of business in which any respectable
gentleman would ever be involved.

But none of that really matters to Crusoe.
As he's not a gentleman, he doesn't feel the need to live up to the values of a class to which
he does not belong. Like any self-respecting bourgeois trader, he is motivated purely and solely
by the desire to make a good profit, however disreputable the means.