We will NOT change this for you. There are no exceptions. It doesn't matter if their username is "offensive"; it doesn't matter how many people they have added "against their will"; it doesn't matter how many people have asked to be removed; this time isn't different/special/an exception; we are not greatest journal; we are not friendster; IT IS NOT A VIOLATION. People. They can see your journal ANY TIME THEY WANT, whether they list you as a "friend" or not.
If you're so sensitive to the issue that you absolutely, positively can't stand to even think someone you don't know/want to/is creepy etc is looking at your journal FOR GOD'S SAKE DON'T POST IT ON THE INTERNET. There are dozens of people (maybe *gasp* hundreds!) reading your journal EVERY DAY that you don't know about because IT'S THE INTERNET. Unless, of course, you post only friends only or private entries. DEAL WITH IT.
Besides, I can absolutely guarantee the trolls aren't really reading your journal. They're trying to get a rise out of you AND YOU'RE GIVING IT TO THEM. Here's a clue for you: If you don't give them any reason to notice you (don't comment in an outraged fit, don't have a tizzy in your journal, COMPLETELY IGNORE THEM), not only will the big, bad, creepy, "serial adder", TROLL not even *think* about reading your journal, they'll ignore YOU too. It's simple; they want a reaction. Don't give it to them, and they'll ignore you in favor of the people who DO.