So which states require an employee to have telemarketing licensing, you ask?
Alabama, Arizona, Colorado, Delaware, Florida, Idaho, Indiana, Kentucky, Louisiana, Michigan, Mississippi, Montana, Nevada, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Texas, Utah, Vermont, Washington, West Virginia, and Wisconsin.
Note that a lot of these states in this list are Republican controlled states, with the exception of some of the northeastern states such as New York and Vermont. Maybe those Republican states, like Florida, see it as a money making venture for themselves.
As for the Northeastern states, they probably have purer reasons to require boiler rooms to do this. It is a good business practice, after all.