They can sue you but the insurance company is liable for the verdict so you won't have to pay it. Generally speaking the insurance company prefers to settle these cases because its more convenient to their clients and is often better for them financially. Victims will generally agree to settlements because they often have significant costs and don't want to struggle with medical and legal bills in the hope of a payout several years down the road.
Most insurance companies require you to sign over all negotiating privileges as a condition of the insurance. So you wouldn't be allowed to dispute things like who was at fault with the settlement, and they could settle 'on your behalf' without letting you know any details of the settlement.
The insurance company doesn't mean the lawsuits don't exist it just means it won't be you who pays them.