~snip
>My question is: why should I be more reverent of marriage than I am of other cultural phenomena like building a multi-level parking garage, making apple pie, or doing the Hokey Pokey?

One of the reason people get married is to raise kids and to have a secured environment for the family unit.
Yeah, with humans in control, half the time, it doesn't turn out that way. Too many people get married for the wrong reason and ruin the lives of others (mainly their childern's lives).

Still if marriage is taken more serious by those that are in one, it's the best thing for the childern.

It's all about what is the best for the childern. I for one strongly believe the best situation for childern is a man and a woman parent.

Unless you are a parent yourself, I don't expect you to understand.