This pattern seems to come up a lot; I just had the same discussion around the Citizens United ruling here.

There is always going to be an uncomfortable point where you draw a line that isn't quite fair, where up to that line is fine and doesn't really do much harm, but crossing that line would be a detriment to the public interest, and so the liberties of the one end up curtailed in the best interest of the whole.

Legally defining that line will always be a challenge. And there will always be people that question exactly where the line is drawn and want it moved further. And in some cases, some people won't want any line whatsoever.

Let's take free speech. I support this 100%. Even if it means defending the KKK's hate rallies, the WBC's protesting of military funerals, etc. I even take it further and don't support obscenity laws. It's not free speech if you can't say something just because someone else thinks it's 'obscene'. I go as far as supporting eg Handley in US v Handley on the importation of loli material. Yet even I will draw the line at real pictures of victims (I believe your freedoms end at the point they harm someone else's freedoms), so some might even say I'm not a true supporter of free speech.

Let's take capital punishment. If you are for executing terrorists or serial killers, then why be against murder in general? I mean, where do you draw the line? What about self-defense in the case of home invasion? That's okay too? What about self-defense against a brutal assault (that wouldn't kill you)? Is that okay? What about to stop someone from stealing your car? You can keep whittling this back and eventually say, "well we shouldn't make any laws against murder, because it's too hard to draw the line!", which is silly.

If you're against the death penalty, then how about drugs? Why do we allow alcohol when it causes more harm than weed? Okay, let's legalize weed (which I support.) Now what about LSD and mushrooms? Let's legalize those too (I also support that.) How about crack cocaine, heroin, crystal meth and krokodil? (I don't support that.) But wait! How do we draw a line here? We should just legalize everything, right? Well ... no. When a heroin addict can't get their fix, they'll start breaking into cars and houses to get money for their habit. They'll end up in the ERs and racking up bills that you and I end up paying in the form of increased insurance fees to pay for them. Whereas someone eating mushrooms is just going to feel great for six hours, throw up, then feel bad for two hours, then go back to their everyday lives.

There are cases where no matter what we decide, there will be consequences. You can be pro-choice, and that's to the detriment of all the children that won't ever be born as a result. You can be pro-life, and that's to the detriment of women who are forced to act as breeders against their will and be saddled with huge amounts of child rearing pain, a child, possible medical complications, huge amounts of debt, and very little to no real support for it.

Real progress in society requires us to say, "damn, yes, this is a really hard problem! How do we improve things?", not throw our hands up in defeat and effectively embrace full-on anarchy.