> do you or would you be willing to extend this line of reasoning to child porn?
No, because that's illegal.
Slippery slope morality arguments are stupid and deserve to be treated as such. I've already heard this a thousand times with homosexuals. Men fucking men? What's next, men fucking kids? Men fucking dogs???
No, it's a stupid line of reasoning and, in fact, it's so stupid that even just a few seconds of inspection is enough to have it crumble and fall between the cracks of your hands.
> As in, some people want to watch it, and most people find it repulsive
You have a very fundamental misunderstanding here.
Okay, people find murder repulsive too. But is the reason that we outlawed murder because it's repulsive? Think about it. Throwing up is repulsive. Do we throw people in jail if they feel sick?
No. Whether or not ANYONE thinks something is repulsive is completely unrelated to if it should be allowed.
We did not, have not, and will never ban child pornography on the grounds it's "repulsive". It is, but that doesn't matter. We ban it because children are unable to consent, and subjecting unconsenting people to sexual acts is rape. Distributing the material is equally bad because it creates a market for it - meaning, more rape.
> If not, where do you draw the line? And why there?
When it comes to sex, consent. That's the only place you can draw the line. Otherwise I can easily weaponize your arguments against you. There are many sexual things you personally do which I find repulsive - please, tread carefully. This line of reasoning is dangerous.