Of course, you're right. Along that same line of thinking, you could hire a contractor to build your house, even though he has never done it, has zero training, has zero real life experience with building a house, but has watched every episode of "Home Improvement" and "This Old House". Please call me after he's done and let me know how it goes.
tl;dr
There are some things in life that must be experienced before they can be understood.
What did you feel when Corbin said fans can't criticize players because they never played in the NBA?
We are observing the life around us all the time. Most of us come from families so we see the inner workings of the relationship between wife and husband and since we see it, we can generate ideas about how some problems can be solved or what creates the problems. It's just not family too, we have friends or relatives who are married and some of them do talk a lot about their marriage, come to us for advices and stuff. We also go through relationships ourselves. Even though, it is not marriage, it can be called marriage-lite. All of this give us a right to speak about marriage, it just doesn't mean we will do all the right things in our marriages. My advice to you is that you should always consider what people say about you and your life. Even if it is from Dala.