That also can indicate something like "There is a community which prefer to be closed for new members and that's why they use some words that only they can understand clearly". I believe that the web-site with translations should be understood by people, who did not read lesswrong.com in English some time ago, and can not see familiar words. The more terms can be correctly comprehended by newcomers, the better for this rationalists community.

True; introducing new loanwords more or less at whim is an old and accepted tradition in Russian, too, although it could occasionally make one look like a snob/hipster.