The Maquis were right in there cause. The Federation had no right to just give away those colonies without atleast asking what the people who life there think about it.
Actually, the Federation had every right.
And if you recall from the TNG episode which established the Maquis as a concept, the colonists WERE asked about it - and it was their bloody idea to stay in the DMZ in the first place! They knew full well that they would be living under Cardassian rule. They insisted on it!