Religious laws do not trump secular laws in the US. And least of all in a person's mind. If Maher does not consider himself a Jew but a Catholic, then as far as he is concerned, he is Catholic, regardless of what Jewish religious laws says about him and his ancestry. If any secular laws have any involvement in his religious affiliation, then it will be from what he declared himself, not that Jewish religious laws says about him and his ancestry.
But if you are willing to go that route, would you say that Barack Obama is a Muslim because his father is a Muslim and under Muslim customs, Barack Obama MUST be a Muslim ?