So many things wrong in this article:
1. The group is the Israeli version of the Westboro idiots.
2. This is NOT an interfaith wedding. The idiot lady converted (which she will regret, but has the legal right to do under Israeli secular law, at age 18). It’s fairly common, and yes, Christians become Jewish, muslims become Jewish, and Jewish people convert as well.
3. The issue is confusing because Jewish law does not recognize conversion FROM Judaism (a view I agree with theologically -— but disagree the State should have anything to do with it -— the issue is between this woman and G-d -— and will haunt her children).
4. Part of the issue is also that there is no secular marriage — you have to be married by your religion, and can’t be married if you have no religion. This was done, in no small part, to avoid gay marriage in Israel. A by-product is secular couples (like this one probably is) fake converts to Christianity or, more commonly, Islam.
Is that true? My understanding has always been that marriage has been in the domain of the religious authorities in Israel (as opposed to the civil authorities) since the state was established (and well before that, under the British Mandate, and even under the Ottomans).
It now has the effect of precluding same-sex marriages, of course, and that may be a significant reason it has not changed in recent years, but I don't think the lack of civil marriage in Israel was done in order to avoid same-sex marriage.