Watchtower considers masturbation to be a form of uncleanness but not a disfellowshipping offence because the bible says nothing about masturbation. A JW who masturbates is likely to face no more than losing privileges in the congregation.
Like masturbation, smoking is considered by JWs to be a form of uncleannes and like masturbation, the bible says nothing about it. But a JW who smokes faces disfellowshipping.
Yes, smoking is known to be deleterious to a person's health whereas the jury is still out on the adverse health effects of masturbation. But if this issue of harm to ones health is the defining difference that causes smoking to be a disfellowshipping offence then what about many other practices that are known to pollute the body and to be deleterious to health; why aren't they also disfellowshipping offences?
For example, shouldn't JWs also be forbidden on pain of disfellowshipping, from eating certain foods that are known to contain carcinogens which pollute the body and increase the risk of cancer? Barbecue and many smoked and fried foods are known to be dangerous to one's health. What about certain occupations that necessarily expose one to certain toxic substances that pollute the body and can be deleterious to ones health just as much as smoking? How can it be OK for a JW to engage in these with no repercussions but smoking is not OK? Isn't that hypocritical?
Shouldn't Watchtower's position on smoking be the same as it's position on masturbation - spoken against as a form of uncleanness; removal of privileges if you practice it; but no DFing?