You know, it's pretty easy to understand why Salomé acts the way she does. Really, it is. We're not being (totally) sarcastic.
All you have to do is look at her final speech to Jokanaan. "I saw thee, and I loved thee," she tells him. "Oh how I loved thee! I love thee yet, Jokanaan, I love only thee" (375). Now, you might say, "This is totally nuts! …and you may be right. There really isn't any reason why she feels the way she does, or any logic to it—although, judging by her mother's reputation, it might be something genetic—and that's the point.
Her reaction is purely emotional, purely sensual. Her love is completely unrequited. Jokanaan wants nothing to do with her, but unlike many scorned literary lovers, she does not give up.
Nope, Salomé doesn't bow out quietly. She doesn't off herself, either, like the young Syrian. She's more of an interesting character than the Syrian is—she's set apart by her persistence, by her willingness to go beyond the acceptable limits. Actually, it's not so much that she's willing to go beyond, it's that she's unable not to. This chick is nuts for her loverboy. Her heart, her passion, is totally inflamed—she has an unquenchable lust for beauty, for the body, for pleasure. All she wants (and all she can think about) is kissing Jokanaan's mouth.
It's pretty romantic…unless it's really nasty and gory.
If we look at things from that perspective, well, she's ultimately fulfilled: she gets what she wants. Her last line is this: "But what matter? What matter? I have kissed thy mouth" (379). It doesn't matter that that mouth was the mouth of a dead man—you get the sense that Salomé would have done anything to get her away. Herod just made it really easy for her to get what she wanted.
To put it mildly, Salomé is an extreme character. Somebody turned her on…and broke the switch. She has a totally self-immolating desire: she's burnt up by it even as it is satisfied. She falls down, down, down into a burning ring of fire—and we mean that in basically the most gruesome way you can imagine it.
Her death and (if Jokanaan is to be believed) damnation don't matter to her, though. She gets what she wants.