I do not like it when people announce that they wish to form communities I would be unwelcome in because of a "protected" feature (sex/sexuality/race/whatever).

I would recommend that you make an attempt to free yourself of this dislike. While some 'protected features' have few real consequences (skin colour won't make you out of place anywhere except possibly a tanning salon), many do, gender definitely being one of them. Sometimes it will be easy to ignore or work around those consequences, and sometimes it will not.

If brazil84 does sincerely find that his ability for rational discussion is hampered by female pheromones (metonymy), and you do happen to emit female pheromones, you certainly shouldn't be blamed for that, but neither should he - it is a weakness of him, but one that falls well within the demands of a modern and open society. While you are absolutely required to behave in a civil manner even in the presence of romantic attraction, it is acceptable if it causes you to perform less than optimally.

As long as he (a) recognises that in a modern and open society, he will eventually need to learn to think and behave rationally even when surrounded by women, and (b) does not by his actions prevent women from joining a rationality club, I do not think he is going out of bounds when he wishes to establish a group that caters to this need of his.

I hate that I cannot come up with a better, less loaded example (I fall into a pretty damn privileged demographic), but: I would understand if I needed to join a rape victim support group and ran into one that wouldn't let me in because the women members were uncomfortable to talk about these experiences around a 191cm / 90 kg bearded deep-voiced man. Of course, I would find it unacceptable if that were the only support group in my area and it chose to leave me completely in the cold rather than create some discomfort to other members.