A true Conservative would not view it that way.
You agree that marriage is not specifically addressed in the Constitution. That is correct. That you use equal protection to support your argument is interpretive in it's application to marriage.
Since the Bill of Rights, although 10 Amendments, are as much a part of the Constitution as the original document pass just a few years prior to them being added. At least you got that the belief the 14th amendment equal protection clause is interpretive when it comes to marriage. What you don't seem to get is that the word "marriage" doesn't exist in it and that should take precedence over what someone thinks something means.
The 14th amendment has already been interpreted to cover marriage in earlier court decisions (Loving v. Virginia), thus there is a precedent for using it to examine gay marriage. Something doesn't specifically have to be addressed in the constitution for there to be a role in interpreting whether a statute is relevant. For instance, drones aren't addressed in the constitution, but the court will be eventually examining the legality of these items in light of prohibitions against warrantless searches, etc.
And, I'm not a conservative.