Its not an assertion, it is an argument. If you are unable to follow the argument, tell me where you get lost and I can clarify.
Again, I don’t see any hypocrisy there… primarily because I reject your assertion that “fairness” in the tax code is in some way a distinct part of the liberal platform or mindset. “Fairness” is just a meaningless word that both sides use. Do liberals want fairness in the tax code? Sure. So do conservatives. They just strongly disagree with what that means.
So what actually IS hypocrisy, in the context of a political party? I’d say it would require a situation where you could describe to a naive observer all of the positions and statements and principles that the party claims to stand for (particularly focusing on official or quasi-official things like public statements from elected officials, party platforms, etc., as opposed to just “all of those guys say X” type of things), then describe to that same naive observer a situation in the real world, and two diametrically opposed possible reactions to that situation, and have the observer say “ahh, clearly the party would support X”, when in fact the party supported Y.
By that standard, I don’t think there are that many issues where either party is outright hypocritical… perhaps the clearest is the right’s opposition to legal marijuana.
Without reigniting SSM Debate XXXIV, I would just point out that many laws are imperfect for administrative convenience or other reasons.
Does it make sense to require seat belt use in cars when the same state would allow me to ride a motorcycle with my entire body without protection in a crash? Well, no, but encouraging seat belt use doesn’t mean that every comparable activity has to be made equally safe.
Likewise, in defining limits on marriage (and there are limits: close relationships, age, two humans, passing a blood test, polygamy, same sex?) a legislature doesn’t have to be absolutely perfect in its definition.
Some incestuous couples may not have mutant children. Some couples who fail a blood test will have sex anyways. Some incestuous couples won’t have children. And further, in promoting a stable environment for children, they could similarly limit marriage to opposite sex couples only, even though many of those couples won’t have children. We have never, in history, demanded that absolutely nobody fall through the cracks of a law, or that it’s effect be 100% fair for everyone.