I know it degrades the santity of marriage
There's sanity in marriage?
Do you mean sanctity?
Obeying the wishes of your parents, honoring and respecting the leadership and choices for your family, would be the reason behind allowing them to select your marital partner.
That being said how would doing so violate the sanctity of marriage?
You can't pick and choose which portions of religious doctrine you apply, folks.
OP, your use of language is a slippery slope.