Dear “Get the fuck out of my LJ”-sayers,
There is a rule, and it says “Your LiveJournal is a public journal by default.” If you want your LJ to be a private space (like you do), by all means make it friends-only; until then, shut the fuck up and suck it up that strangers may eventually stumble upon your LJ, leave comments, or initiate various forms of relationship with your “friends” without you in between them.
You see, there's this thing called “free will.” It's not just you that have it. Your friends do. Strangers do too. So stop thinking strangers invade your “privacy” if they start talking to each other through your LJ. They do not require your authorization to do so. Just suck it up, and STFU. Or make your LJ friends-only. Worried the “OMG this journal is friends-only, ask me to add you” post would make you look uncool? Suck it up too, because that's a price you have to pay.
Just remember, whining about such things only makes you a tantrum-throwing crybaby.
Hope this helps (you grow up),
P.S. *sigh* This is what I get for deciding to try the [ “Latest Posts” ] feature on the front page, which, given the vast number of LJ users, essentially serves as a “Jump to a random LJ” feature.