Because it re-wires the brain, makes you sex obsessed, makes you socially awkward, causes people who commit masturbation in some cases depression, and it's easily addictive.Ask yourself why something that can be healthy, alleviate stress/pain, create joy without no objective harm is deemed haram?
I shall be waiting for the rational answer
The only reason why you are defending it is because you do it yourself.:siilaanyosmile: