I’d say the right to life was the most important right. After all, if someone violates our right to life, then all other rights are automatically infringed as well (we are dead).

You’re veering dangerously close to libertarianism and extreme property rights (“You own yourself” with no infringements permitted).

“‘Well, it’s OK for other people to kill those persons, I just won’t do it myself.’
That might be what moderates (non-religious even) people might say, but sadly the adament [sic] pro-lifers feel the need to win us all over.”

Ca’t you see how morally repugant abortion is to those who believe the unborn are human? They feels the same way about it as you would if millions of new born babies were killed every year, or the murder of old people were common. Imagine how absurd it would seem if you were protesting against such widespread murder and someone said to you, “If you don’t want to kill 2-year olds, it’s fine. But keep your beliefs to yourself”.

They view human life as sacred and they’ve decided that a fetus is a human being. Let their beliefs guide their own body then. Sadly the movement as a whole has veered hugely off of this simple path.

In fairness to the abortion prohibitionists, if they truly believe that a fetus is a legal person (which I doubt they actually do believe — they never can answer questions about the consequences for inheritance law, citizenship law, etc. of actually treating fetuses as persons, but whatever), then they can no more limit their beliefs to their own bodies than abolitionists could limit their beliefs about the personhood of blacks to their own plantations.

The fact that forcing women to keep the “legal person” alive intrudes on the most basic liberty, that of the body, means that there are issues in abortion that did not exist in slavery (the only “liberty” at issue there was the freedom to own other human beings instead of paying freemen for their labor). But once you believe that a fetus is a person, you can’t say “Well, it’s OK for other people to kill those persons, I just won’t do it myself.”

Validity is a precise logical term. An argument is valid if it is impossible for all the premises to be true but the conculsion false. There are many arguments that are valid but that no-one would ever accept as sound or even consistent – such as arguments with contradictory premises eg

Premise 1 I took a history exam yesterday.
Premise 2 I did not take a history exam yesterday.
Conclusion My name is Anna

Clearly this is a ridiculous argument – but it is valid, since it is impossible for the premises to be true and the conclusion false. (It doesn’t have a valid form, but that’s another issue).

So we can’t use “valid” as a synonym for “good” or “acceptable”.

Also, that ‘marriage has always been intended for procreation’ argument drives me batshit, because it’s not true. Historically, in the West, marriage was intended to regulate inheritance and property, and provide a framework in case procreation took place. There was a reason why in so many places married women couldn’t own property or enter into contracts. There was a reason children born out of wedlock couldn’t automatically claim any rights to the property of the father. Property of the family – ie the men – was the main point of marriage. Not procreation per se.

Seriously, what is with these people? We have marriage for straight couples. We want marriage for gay couples. It’s not a slippery slope. It’s not even a slope.

Yeah, because, he, you know, actually is defending Britney’s marriage. He thinks it part of the bedrock of society. And any gay marriage, any one at all, would be so much worse than Britney’s marriage that it should literally be illegal. He might not want to admit that that’s what he’s arguing, but it is, in fact, exactly what he’s arguing.