The headline is an example of “yellow journalism”. Saying an eid is pasul means you are holding that the marriage is invalid, such as when one is trying to prevent a child from being a mamzer or prevent a woman from being an agunah. These are legal rulings.
Picking an eid for the wedding is a social activity, not really a legal one, and the Rav’s statement was political not halachic. If it were necessary to uphold the validity of a marriage (as occurs if the husband dies and one wants the surviving woman to be a widow rather than a girlfriend), I seriously doubt he would hold the marriage invalid.