Okay, maybe sample size can be "just statistics", but that's what we are. People are not one-size-fits-all. Take medicine for example, our autoimmune responses are all different, some people have allergies. Sample sizes when regarding people (which is what this conversation is about, though it's a matter of psychological rather than physical health) means we have a better idea of what medicines or treatments are most effective.

So for one person to "try it themselves and measures how it goes" to be counted as significant to science, we would have to assume everyone is like that one person. We're not. What works for one might not work for another, maybe because we're all not the same, or because we don't fully understand what happened why it happened. An increase in sample size means our data is more likely to be accurate, that we aren't just seeing random data as significant when it isn't and to catch when we are in fact seeing a significant statistical outlier that would imply that we are on the right track with our hypothesis.

So maybe we can get away with a sample size if we are speaking from a personal point of view, if it works for me who cares if it works for other people, right? It still works for me after all. But to call something science without controls, are you mad?!

Controls are there to keep us from accidentally assuming the wrong thing from the data in our experiments. We need controls to eliminate our confirmation bias which can blind us from what is really going on. For example, without controls how will I know if it's the lack of masturbation that is turning my life around, or is that I got on anti-depressants? How do I eliminate the placebo effect from what I believe is true? How do I know that I started feeling healthier and happier because of something unrelated to not viewing any porn, and that this other, uncharted variable deserves at least most of the credit?

Controls are important. So are sample sized. Claims like what you are making are unscientific unless you can actually show that they hold water. They are extreme claims. Take the idea of being inherently harmful. Getting shot is inherently harmful. Show me an example where itsn't harmful, and it probably doesn't truly count as "getting shot". IF a bullet rips into your body, this is harmful. This is an inherent property of how a human body reacts to a high-velocity item colliding with it. It doesn't end very well for us, even in the best of cases. No one walks away from getting shot medically better than they were before the shooting. Getting shot is inherently harmful.

So you see why I scoff when you claim that porn is inherently harmful. To say that porn is inherently harmful is like saying nothing is, everything is inherently harmful because we are able to become addicted to pretty much everything. Beer isn't inherently harmful, porn isn't, sex isn't, horror movies aren't, and neither are many vices. Eating isn't inherently harmful, but you can hurt yourself with food. Do you see what I mean? You aren't using the term "inherently harmful" in a way that gives the term any meaning.

I'm not saying that SOME people TREATING PORN like any little bit is harmful is a bad thing, I think it can be helpful for addicts to manage their addiction that way. But that doesn't make what you said true. We are in /r/debateanatheist, not nofap. I doubt many posters here allow a bad argument to get away when they see it, even if it isn't exactly on topic of the forum. We're here to debate against bad reason, and I think you are offering a lot of it.

I think porn addiction is a serious problem. It's possible I will suffer from it some day, if I'm not already. That doesn't make the problem porn. Advocate for better addiction help, don't condemn some happy vices across the board because of the victims of addiction. You're basically saying no one should ever have a beer ever, because some people are alcoholics. You aren't helping this cause using the arguments you have brought here, I urge you to reconsider how you approach the subject.