The word "lesbian" itself comes from an island that way so full of 'em you were persecuted for not being one; an island the Greeks visited quite often.
Wait, what? Where on earth did you hear that from? To the best of my knowledge, all we know for certain of the island of Lesbos, which is where the word lesbian comes from, is a few scraps of Sappho's poetry about the daily lives of girls who were left in her care to be educated. Some of that was love poetry directed at some of the girls, but nothing about it being a lesbian-only culture that had any power to persecute anyone. If anything, the suggestion is that it was more like an artist's retreat. Are you confusing it with the (highly apocryphal) stories of Amazon women killing male babies or something? I certainly can't find anything, reliable or not, which suggests that sort of thing happening on Lesbos in any case.