Native English speaker here. Honestly, that response is perfectly acceptable (though not punctuated) if taken in context. I was skimming through, and it appears to be the poster's response to the immediately preceding post, answering as his version of the MC, that, given the choice of a harem or monogamy with Rachel, he would choose "harem". I didn't even think about it until I saw these two responses to it.
What is missing from his two word response, if taken on a stand alone basis, is the context. Had he quoted the thread he was responding to, then the context would have been readily apparent to all and a simple response of "Harem, please." perfectly acceptable for most. Because of the way I was going through the thread, I connected the response to the previous post, generating the context in my own mind without the visual cue of a quote.
Here endeth today's colloquial English Grammar lesson.
