It's an abuse of a bodily function against its proper ordering. In other words, it's an attempt to enjoy a side-benefit of eating (pleasant taste) while rejecting the paramount purpose of eating (nutrition and sustenance). This abuse naturally results in grave damage to the body over time.
It's perfectly analogous to onanism or contraception which is an attempt to enjoy a side-benefit of intercourse (physical pleasure) while rejecting the paramount purpose of intercourse (procreation).
But let's flip all the cards, and let me present to you the same question that I proposed to steve-b.
Is suicide morally good, evil or neutral?
Would you remain neutral to the suicidal intentions of your mother, father, sister, brother, son or daughter? If so, what would that say about you? Would that make you a paragon of virtue, or loveless and hard-hearted?
You need to find a different word, then. "Malice" means a desire to harm others, or to see others harmed.
Is suicide morally good, evil or neutral?
I think it depends upon the circumstances. For someone near the top of the World Trade Center on 9/11, was it morally evil for them to jump rather than to die in the fire or building collapse?
Masturbation and true contraception are not equivalent to suicide. There is no loss of life with the former, while there is with the latter. The right not to be killed is inalienable - it cannot be given away any more than it can be taken without infringement of that right.
The prohibition against true contraception is a religious matter. The legitimate function of the government is only to protect rights of humans. There are no rights violated by contraception or masturbation.