Who knows if they were insecure or not, but why would you care at all? You're going to be there for an hour or less, get on with your practice. If they're being obnoxious or unsafe, alert the driving range management or just move away from them. They may be obnoxious, but you're making it your problem too, that's up to you alone. With all due respect (sincerely), you must be pretty young, still worrying about things you probably can't change, life's too short.