I never understood why is it wrong to say that it is wrong to use violence.
I believe that is a double negative, if wrong is interpreted as a negating qualifier. Your ideas about violence are incredibly naive. As Heinlein points out, violence is the SUPREME authority, from which all authority is derived. It is why the victors write the history books. It is the reason why American revolutionaries are not described as traitors and the Left is now rebranding Confederates as traitors.
If I am not mistaken, one the Navy Seal unit has as its motto "“
Despite what your momma told you, Violence does solve problems.”
There's a reason I myself believe that anything you yourself do, you immediately lose the right to criticize others for that same thing.
That's silly. A relapsing heroin addict or alcoholic is probably in a better position than anyone to explain why it is wrong and you should not do it.
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Concerning moral-fagging, it is interesting people have different definitions. It is internet slang so I try not to use the term in other contexts. Whenever I think of a more formal expression, I think of the term "moral-trumpeting." (Nietzsche famously derided Schiller as a "moral trumpeter." Moral grandstanding or finger-wagging also works. In my mind, moral trumpeting or moral fagging is associated with a deep impracticality, or demonstrative finger-wagging that seems to overlook critical points or considerations.
Two examples that exemplify obnoxious moral-fagging come to mind. A Christian who is adamant that sex before marriage is wrong, but does not seem to discern hormones are real and people no longer marry at 18, 19, 20, thus expecting somebody to abstain well into his 20s or even 30s, which is not healthy (not that hyper promiscuous sex is either) and not practical. It is an unreasonable moral demand that makes
no account of the facts on the ground.
Example two--people who take the United States drinking age of 21 seriously. College kids under 21 drink. Most high school kids drink, and those that don't are typically socially isolated. All our stupid drinking laws do is make a big deal out of it, which leads to things like binge drinking, which does not exist in Europe because minors can drink beer or wine no problem. The 21 law was on overreaction to MAAD (Mothers Against Drunk Driving) and is only tangentially related to the problem of drunk driving.
I do think there is an element of hypocrisy or grand-standing with these things, because I doubt most who defend the drinking law really abstained from alcohol till they are 21, and if they were they were not the sort I would want to hang out with when I was young and i doubt I would want to hang out with you as an adult.