If you didn't do anything wrong, there would be no grounds for a ruling against you. By settling, you acknowledge that there's some grounds, just not the full weight of the accusation made. Yes, some companies would rather settle so it gets out of the media and they don't have to face a ruling against them in the end, but that doesn't mean they did nothing wrong. If they actually did nothing wrong, fighting that in court and establishing how baseless the accusation was is the way to go, in many cases.
Hell, I've had someone try that bullshit with me; I had a car accident a few years back when a guy pulled a U-turn through overtaking traffic (me). The police investigation based on our separate accounts, and the insurance company investigations by both of our providers, all concluded that he was 100% at fault. The guy still sued me not once but three times. My response was to say "fuck that noise", and send it along to my insurance company to get their lawyers to have the suits dismissed. My reaction was not to pay him the $1000 or whatever he was asking, because I had no culpability whatsoever in the accident. Agreeing to pay would have admitted that I had.