There is an apparent juxtaposition here, between the rights to believe and say whatever you want, and the rights of the audience to be protected from acts that interfere with their security, which may result in mistreatment, etc.

I say “apparent,” because there is no conflict here. The Universal Declaration of Human Rights is a singular declaration, not a combination of individual articles. The right to expression is there as long as that expression does not interfere with any of the other rights granted the audience. Freedom of Speech is not the primary right; it is part of a larger whole that in totality provides us all with freedom.