IQ 145+ reasonably fit/attractive men around my age who happen to be sympathetic to transhumanist values

You're not me, but if you are anything like me, this will probably be one of the things you change your mind about in the future.

After switching "men" to "women", everything in your comment would have rung true for me from a younger age (15-19) - I was primarily looking for someone highly intelligent (though my cut-off was more like 95% than your 99.9%) reasonably attractive, socially liberal and sex positive...and even though my requirements were way less stringent than yours, I still was turning down advances from people who, had I got to know them better, might have turned out to be perfectly acceptable. I'd say I considered maybe 1% of the people I knew well enough to judge as acceptable partners.

Once I actually started having experience with real relationships, everything changed. I'm equally picky for serious long term relationships now (though I'm more willing to do casual stuff now than I was in the past) but today my "bottleneck" criteria that most people fail have mostly have to do with kindness, communicative skills, and emotional resilience. I still care about things like intelligence and attractiveness, but not nearly as much. To me, intelligence is sexy signalling in the same way a fit body is - I'm instinctively drawn to it and a total lack of it will turn me off, but I don't attempt to consciously evaluate it as a relationship criteria anymore. As for ideology, I find that most people who possess the qualities I care about either already have worldviews which I find acceptable, or tend to alter their worldviews after discussion.

I wouldn't say my actual criteria changed, only my knowledge of what my true preferences actually were. Regardless of the criteria you think you have, your true preferences will shine through eventually in the form of break-ups and relationships that fizzle out before they start. But if you're working with a layer of false criteria on top of the true preferences, you might turn down the opportunity to connect with someone who does not meet your false criteria but does satisfy your true preferences.

(For reference on how to weigh this info, I'm 23, I've been in a happy relationship for 4 years with several shorter non-consummated interactions before and during, and the only major stumbling block has been different monogamy/polyamory related preferences)