That is the most annoying response. I mean seriously, it's an 8 minute video. If you're too lazy to watch the video, then why post in this thread? But to appease you, I'll try to sum up what that video says.
It's basic premise is that no one follows the Biblical view of marriage anymore, and people are cherry-picking one aspect of Biblical marriage and choosing to set it as an unmovable tenant, even though they have abandoned other views of Biblical marriage. So what is the Biblical view of marriage? you cited the Old Testament, let's look there.
Polygamous relationships were not uncommon as many prominent historical figures had multiple wives at the same time (Abraham, Moses, David, Solomon, etc.). In addition, there were traditional marriage rules, such as: rape victims must marry their rapists; if a woman's husband dies, she has to marry the brother's husband, even if he's already married; interracial marriage is prohibited; and if it turns out your wife lied about being a virgin when you married her, you have permission to stone her. These are God's laws in the Torah, not man's laws. Women were viewed as property. This was traditional marriage.
The video goes on from there explaining how marriage kept on getting redefined over the years. These were entire civilizations of people, Christian and non-Christian, who viewed marriage in ways that are incredibly foreign to us. Examples were then given of other more recent changes to marriage laws, including allowing interracial couples to get married, something that people discriminated against well into the 20th century, using the Bible as support.
SUMMATION: If I were to sum up the point of the video, and of this topic, into a nutshell, it would be that the Bible says a lot of things about marriage that no one follows anymore or believes to be appropriate, even though there were entire civilizations who followed some of these rules for thousands of years, some rules only recently falling to the wayside. Yet Christians hold on to this "one man one woman" thing as if it somehow supersedes the other marriage rules that they currently ignore today.
