“Can” vs. “May”: The Difference is Important

Leftists are opposed to Uber, etc. because of the following simple syllogism:

1. Under laissez-faire capitalism, businesses can do anything they want.
2. Businesses want to suppress competition.
3. Laissez-faire capitalism will thus lead to monopoly.

They went wrong at just one word: They think laissez faire means “businesses can do anything they want” instead of “businesses may do anything they want.” I suspect some of them simply do not know there is a difference.

On the other hand, according to stereotype, English majors are more likely to be leftists. Shouldn't they, of all people, know the difference?