What does Roosevelt mean when he says a muck-raker is like a person who "fixes his eyes only on that which is vile and debasing"?
He is comparing muck-rakers with people who enjoy creating problems.
He is comparing muck-rakers with people who focus on negative things.
He is establishing a standard from which to judge whether people are good or bad.
He is establishing a standard of what is good muck-raking and what is bad muck-raking.