Unfortunately, the author engages in a logical fallacy, post hoc, ergo propter hoc.
While Cardinal Kasper makes the statement about heroic virtue, the statement isn’t equivalent with the Pope’s statement.
When one looks at how many Americans are civilly married, it is likely that half have no serious commitment to “... death do us part,” nor to procreation. In those cases, and ONLY from a religious point of view, can those marriages be considered invalid.
I don’t agree with Cardinal Kasper. However, I do agree that marriage and Holy Matrimony haven’t been taken seriously. I also agree, that is likely there are an enormous amount of marriages that are/were “defective,” by religious standards. However, I don’t really know what to do about it.
“However, I don’t really know what to do about it.”
IMHO, you do your best to do what you believe is right, and put your faith in God’s wisdom and mercy. No one on the planet can read the mind of God, and we are every one of us fallible. Marriages fail. It’s a fact, and a sad one at that. My parents, on the other hand, stayed together and nearly destroyed each other over a lifetime - and the profound pathology led to child abuse. What can you say?