This is a common logical fallacy. We don't incarcerate people for stealing $0.50 candy bars to prevent the theft of further $0.50 candy bars. We do it to preserve the rule of law in our society.
Consider the crime of perjury in federal court. No one is losing money when perjury is committed. But the government is willing to spend millions of dollars prosecuting perjury none-the-less. The reason is the same, to preserve the integrity of our legal system.
So yes, stealing one or two towels isn't the end of the world. But we still prosecute it because theft is bad, and not punishing thieves only encourages widespread theft.