If we're going to take the rights of consenting adults seriously, consanguineous lovers can't be excluded

The blogger answered...
On a totally theoretical level, I have no problem with two consenting, fully aware, informed adults having a relationship just because they share a certain percentage of genetic material.

Good.

However, we have to remember that a lot of incest (though certainly not all) is a product of abuse and happens in abusive contexts.

Well, yes, the world "incest" is applied to the two very different things of consensual sex and assault/abuse, but the person asking was talking about consensual sex. Do we ever say "We have to remember that a lot of intercourse is a product of abuse and happens in abusive contexts?" Do we comment on BDSM by saying a lot of handcuffing has been the product of tyranny or slavery? See Discredited Argument #9.
So….yeah. I mean, we need to be aware and supportive for victims of incestual rape, but I don’t think that incest in pure theory is inherently bad.
I'll take the support for sexual and relationship rights. A woman should be free to marry a woman, or two women, even if one is her sister. That's feminism.

Tumblr is full of fetish porn, which I'm not in any way knocking. I bring that up because it is great to see serious consideration of consanguinamory as part of the mix there.