The rationalist in question, of course, is our very own EY.
Quotes giving a reasonable sample of the spectrum of reactions:
Epic Fail on the e-harmony profile. He’s over-signalling intelligence. There’s a good paper about how much to optimally signal, like when you have a PhD to put it on your business card or not. This guy is going around giving out business cards that read Prof. Dr. John Doe, PhD, MA, BA. He won’t be getting laid any time soon.
His profile is probably very effective for aspergery girls who like reading the kinds of things that appear on LessWrong. Yudkowsky is basically a celebrity within a small niche of hyper-nerdy rationalists, so I doubt he has much trouble getting laid by girls in that community.
You make it sound like a cult leader or something....And reading the profile again with that lens, it actually makes a lot of sense.
I was about to agree [that the profile is oversharing], but then come to think of it, I realize I have an orgasm denial fetish, too. It’s an aroused preference that never escaped to my non-aroused self-consciousness.
Why is this important to consider?
LessWrong as a community is dedicated to trying to "raise the sanity waterline," and its most respected members in particular put a lot of resources into outreach, via CFAR, HPMoR, and maintaining this site. But a big factor in how people perceive our brand of rationality is about image. If we're serious about raising the sanity waterline, that means image management - or at least avoiding active image malpractice - is something we should enthusiastically embrace as a way to achieve our goals. 
This is also a valuable exercise in considering the outside view. Marginal Revolution is already a fairly WEIRD site, focused on abstract economic issues. If any major blog is likely to be sympathetic to our cultural quirks, this would be it. Yet a plurality of commenters reacted negatively.
To the extent that we didn't notice anything strange about LW's figurehead having this OKCupid profile, LW either failed at calibrating mainstream reaction, or failed at consequentialism and realizing the drag this would have on our other recruitment efforts. In our last discussion, there were only a few commenters raising concerns, and the consensus of the thread was that it was harmless and had no PR consequences worth noting.
As one commenter cogently put it,
I’m not saying that he’s trying to make a statement with this, I’m saying that he is making a statement about this whether he’s trying to or not. Ideas have consequences for how we live our lives, and that Eliezer has a public, identifiable profile up where he talks about his sexual fetishes is not some sort of randomly occurring event with no relationship to his other ideas.
I'd argue the same reasoning applies to the community at large, not just EY specifically.
 From Anna's excellent article: 5. I consciously attempt to welcome bad news, or at least not push it away. (Recent example from Eliezer: At a brainstorming session for future Singularity Summits, one issue raised was that we hadn't really been asking for money at previous ones. My brain was offering resistance, so I applied the "bad news is good news" pattern to rephrase this as, "This point doesn't change the fixed amount of money we raised in past years, so it is good news because it implies that we can fix the strategy and do better next year.")