Certain behaviors can and should be curtailed in the interest of societal safety.

In a Democracy, the existence of a political party -- provided they are not actively breaking the law or calling on/encouraging others to do so -- should never be curtailed. Freedom of political expression must be extended to the loons and idiots so as to preserve the full range of freedom of expression.

However, the public is free to (and should be free to) consider members of such parties to be idiots, poltroons, perverts etc.

Freedom to express your views is matched by my freedom to reject and belittle them.