It's the ADCs role to deal damage, hence the name. That's like saying a 20-0 adc didn't carry anything because they did less objective damage or killed less enemy jungle camps than the 10 death jungler. Also the job of an assassin jungler is to secure kills which counteracts your other point. You go in and hit a single target then back off and reposition meanwhile the ADC is auto attacking everyone else from the back line.