So, Catholics see impotence as a valid way to end a marriage?
No, that's not what the quote says. It says that impotence is an impediment to marriage vows. That is, a man who is impotent cannot make valid marriage vows. He cannot get married. It EMPHATICALLY DOES NOT say that a married man who becomes impotent ceases to be married or that his marriage can be divorced. His condition at the time he made the vow is relevant, not a change in his condition after.
If you don't understand the distinction, I'll try to explain further.
I taught at an RC seminary In the 60’s. It was rife with homosexuality. There was substantial confusion about sexuality. Some believed that homosexuality was an acceptable solution to the problem of celibacy. This led directly to the substantial abuse of children by homosexual priests.
It has taken far too long for the church to clear this matter up. I am pleased to hear, finally, that there is an understanding of the relationship between homosexual priests and sexual abuse.