What is the meaning of this quote? What is Theodore Roosevelt asserting about a man with education versus a man without it?"A man who has never...

Theodore Roosevelt was the first of America's three
progressive presidents.  Because he was a progressive, he worried about the power of big
business and the elites who ran them.  This quote shows this
worry.

In this quote, Roosevelt is saying that people with
college educations (who were relatively rare in those days) were more dangerous to
society than those without.  He was saying that a person with a college education could
exploit others on a much larger scale.

If you have no
education, you can only steal by breaking into things, he is saying.  But if you are
educated, you can use that education to steal in big ways.  You can use it, for example,
like Bernie Madoff did and steal billions of dollars.  Or you can use it like a robber
baron to make a monopoly and use that to steal from the the population as a
whole.

So, what Roosevelt is saying here is very much in
line with the progressive idea that elites were a danger to society.  He is saying that
educated people can steal in bigger ways that are more dangerous for society (like
Madoff or the Enron people) while the poor can only steal a little at a
time.