I absolutely hate all the nofap bullshit there is on the internet. The people who support it claim that nofap is supported by science, but it isn't. It is based on bad interpretation of studies. Like the one about watching porn and that it shrinks the brain. That is just bad interpretation of a study that showed a correlation and not causation.

That study suggested that people who watched porn more than 20 hours per week, were statistically more likely to have less grey matter in certain areas of the brain. Watching porn is probably not the cause of this.

Here is a bit about what neuroscientist Dr. Nicole Prause said about it:
Both alcoholism and depression shrink the same brain areas that were found to be smaller in porn watchers in the current study. Depressed people are less likely to be in a relationship, and may therefore have fewer sexual opportunities in real life and more time on their hands to look at sexual content. In that instance, it may be the underlying depression, not the porn itself, altering the brain, Prause said.

But there are even some studies that suggest that masturbating might be healthy. Please, if you find a study that suggests otherwise, post it here.