I actually agree with this. The reason is that many states include far lessor offenses into the sex offender category. I know two people who have to register as a sex offender because they had sex when they were 16 and had a baby. The state of Wisconsin charged them both with a sex offense even though they got married and raised their child. 15 years later they are still registering.
I know someone else who at 19 dated a 16 year old. They are still married after 10 years. And he is required to register.
The reality is that for all of humanity outside of the last 50 to 75 years and in most of the world today teenagers get married. But here and now its punishable with a life sentence of wearing a scarlet letter.
If sex offense was limited to violent rape, or the age of statutory rape was lowered significantly then I would agree with you.
The examples you site shows where the law is messed up. If the law is changed to accommodate these couples then it should be done. Some people just happen to be paired up very young and tend to have the best marriages.