Yes, gay marriage should be an issue left up to the states but that state right will be washed away once the SCOTUS finds a gay marriage ban in violation of the 14th Amendment.
You’ve said this several times on different threads without giving your own opinion on the issue. I find that curious.
Also, it all depends on who is on the SCOTUS when they consider the issue. The current Court might very well split 5-4 in support of that position, but if it doesn’t come up for a few years, then neither you nor I can know how much support a liberal reading of the EPC will get before some future SCOTUS. The current 4-justice “conservative” bloc is the strongest the Court has seen in years. There are no Powells in that group. Those justices will not be swayed like Kennedy, so their positions are their positions. If we have a different prez in a few years and one of the libs goes, all bets are off.