The Hare Krishna airport case to which Prof. Kairys points as an example of the conservative Justices’ supposed inconsistency rested on the government’s power to restrict solicitation of money on its own property. The Court has repeatedly held that solicitation of money for charitable and ideological causes is constitutionally protected. But it doesn’t follow that a government must allow solicitors to the use of the airport that the government owns for such purposes. The majority’s analysis in that case was premised entirely on the government’s extra power as a proprietor of what the majority saw as a nonpublic forum, not on any general right to restrict the gathering of money.
One can debate what the right result should be in such a case (Justice Kennedy, for instance, thought that speech was constitutionally protected even on government property). But that’s a very different issue from whether the government may limit solicitation of money — or the use of money — everywhere, and not just at government-owned airports.