Signing the right to secede is constitutional, and a first amendment right. Exile is not an option for these citizens.

People should not be exiled or deported because they are excercising their 1st amendment rights by signing a petition to seceded from the nation.
The original 13 colonies wished to secede from britain, now many states wish to secede from Washington D.C.
Regardless of if you agree with these people or not, respect their freedom of speech