Reply #1: The reality is no true libertarian can be against same sex marriage.

[Statistical]

It is a logical fallacy.

Olson does lay out the arguments very well.
I always thought that marriage inequality would be found to violate equal protection under the law (eventually).

Marriage goes way way way way beyond a union of two people. It affect taxation, inheritance, insurance, wealth, etc. It is simply IMPOSSIBLE to have a system where one subset of the population is subject to reduced rights and be equal under the law.