JSHint is mostly licensed under the MIT license. I say mostly since it inherits some code from JSLint which uses a modified form of the MIT license. It requires that the software only is used for Good, not Evil.
"The Software shall be used for Good, not Evil."
So the White House is using software that can only be used for Good, not Evil. Which means that if the White House has used its website to do evil, it has violated Douglas Crockford's license.
The next minor version of WordPress removes JSHint, but the inclusion of it will live on in internet archive history.