You, in your own comments, acknowledged they are similar, not identical.
For starters, you have to go abroad for one. https://en.wikipedia.org/wiki/Recognition_of_civil_marriage_...
They also aren't valid abroad sometimes.
"In 2017, the Florida Third District Court of Appeal held that although Israel recognizes 'reputed spouses' as a legal union, the union is not a marriage under Israeli law, and therefore, Florida law does not recognize the relationship as a marriage."
And some people (an atheist marrying a religious person, for example) can't get one at all within Israel.
"In 2010, Israel passed the Civil Union Law for Citizens with no Religious Affiliation, 2010, allowing a couple to form a civil union in Israel if they are both registered as officially not belonging to any religion."
> Also: this kind of discrimination - if there is any - is targeting Arabic and Non-Arabic Israelis in the exact same way.
"It's fine, we discriminate against other minorities!" is not the argument you imagine it to be.