Internet has enabled p**rn to be more accessible than ever before, and strangely it seems more and more are going bald at a younger age.
Exactly.
Masturbation doesn't cause hairloss in people who don't have Androgenetic Alopecia.
Masturbation can however accelerate hairloss in people who do already have Androgenetic Alopecia PLUS are also more sensitive to DHT spikes than typical people who have Androgenetic Alopecia.
So even if it is a small spike of DHT, there are lots of people who have Androgenetic Alopecia that are also sensitive to such spikes which is the reason you will get a lot of people saying they do notice an acceleration of thinning hair/hair loss and itchy scalp.
If someone is on anti-androgens they almost never will notice this itch or accelerated thinning/hairloss post-Masturbation/ejaculation as anti-androgens will have suppressed DHT levels.
Although for many who aren't prepared to undergo the potential side effects of using anti-androgens, they are more likely to experience this if they have Androgenetic Alopecia + are sensitive to DHT spikes.
I have noticed that using vitamins like Zinc, DHA, GLA, I have been able to naturally mimic the beneficial effects of drug types anti-androgen - without the side effects associated with anti-androgens) and after ejaculation I did not notice any itching of the scalp or accelerated hair thinning/miniaturization.
(NOTE: when I was not on any drug anti-androgen I used to always feel my scalp itch followed by accelerated hair thinning/miniaturization - and I definitely know personally that ejaculation/maturation used to always negativity effect my hair)
Ejaculating/Masturbation causes a spike in prolactin which can cause hairloss.
You might have heard about the recent group buy SMI-6 which is meant to target the prolactin pathway, many people believe that prolactin is a very probable cause of hairloss)
You also won't get any/many high quality studies on the relationship between masturbation/ejaculating and hairloss because many people wouldn't want to subject themselves to such trials nor would there be much funding for it.