To discuss this idea, we must first define it. According the the TRP sidebar, the phrase "sexual strategy is amoral" is a reference to the fact that there is no objective morality, and that morality exists simply as a system that benefits society on the whole. For this reason, there's no point in following morality when it benefits you not to.

In other words, the Dark Triad. Act in ways that benefit you, damn the consequences.

The other definition I've seen floating around here, which is not supported by the sidebar, is that sexual strategy in itself, ie; the stuff you read on TRP, is not moral or immoral, and is just words until put into action.

The first definition makes my argument for me. It acknowledges outright that TRP sexual strategy may be immoral, and instead of arguing against that, it seeks to justify it by citing that no objective morality exists. While that's true, morality still has a great impact on our lives. By adhering to the principles that benefits society as a whole, we gain the ability to cooperate. That's what made humanity so evolutionarily successful. Undercut these principles, and everyone, as a whole, is worse off. You've made the world a worse place to live. For these reasons, morality should be a key factor in your decision making.

The second definition claims innocence by stating that simple dissemination of information is not in itself a crime, and that only putting those words into practice is. While sharing immoral tactics is nowhere near as bad as actually using them, it's still wrong, because you've given a predator the tools he needs to commit wrongdoings. You've played a part in someone's misfortune. You are at least partially responsible. For example, under this reasoning, if a method of getting a woman to have sex with you existed, but caused you to harm her as a result, it would be shared. And more than a few would attempt to put it into practice.

Amorality is immorality. Only those who act without concern for what's right can commit the most outrageous of acts. Claiming amorality when confronted with immorality is nothing but an excuse, because, in the grand scheme of things, amorality is no different from immorality.