Amsalem can have whatever opinions he chooses, so long he does not do so under the banner of being a Shas MP. Since Shas put hin 10th on their MP list and gave him his Kenesset seat conditional to his supporting the Shas program, if he breaks that pre-election agreement he made with Shas, he must resign that seat back to Shas.
Before Shas put him on their MP list and made him a Kenesset member, Amsalem was a nobody and no one heard or knew of him.