I think a lot of the confusion in this thread, and most threads about nofap, come from a failure to recognize that masturbation can physiologically affect people differently. There are conditions like POIS, and probably milder versions of it which afflict people. I don't think it is normal to feel bad after masturbating, and I think most people don't. This only seems to be a popular sentiment online, because online communities create an echo chamber effect which normalizes it or amplifies it beyond what would be seen when looking at society at large.

I am not counting any projected negative beliefs about masturbation as an affliction, although this is probably the more common case, where people will simply self-deprecate themselves because of some negative beliefs after orgasming, and then interpret this as "masturbation makes me feel bad!"

I think the genuine physiological affliction is rarer and amplified online. But, the latter more common case of projection is not uncommon at all, and is seen online and in real life, commonly through religious indoctrination or whatever else.

I had this exact contention with @Someone here before, and he ran a poll on the forum, and you might be surprised to find that the majority of people who voted felt completely fine after masturbating: