Yes, Robbie, the bishop in that case was right
Okay, well, I'm a canon lawyer, and I say, it's more than likely the bishop ruled correctly in that case.
To use venerable contract-language, marriage can be described as a complex of reciprocal rights and duties (yes, I know marriage is much more than that, but marriage is at least that, or it isn't marriage), and among those rights and duties figures the performance of acts per se suitable for the generation of children. Thus, if one cannot render and/or receive such acts, one cannot enter a contract that calls for, among other things, just such ability. See generally 1983 CIC 1055, 1061, and 1084. The bishop in this case, guardian of the sacraments in his diocese (c. 392.2), apparently acted to prevent an attempted exchange of consent by a party incapable of fulfilling his (or her) concomitant duty. It's that simple.
Folks wishing to discuss the marriage of Mary and Joseph, or marriages of the sterile, or dissolution of consummated or non-consummated marriages, or the practice of periodic abstinence, should consult the approved authors.