I'm not that good on technical aspects of radars, but the way he's arguing is pretty cheap. No stealth plane to date has been designed to by itself be 100% invisible to radar. The way they've always been supposed to work is in conjunction with most of all SEAD supporting efforts. That's why the only shoot down of an F-117 by the Serbians was on a night when someone decided to press on with the mission despite the complete lack of SEAD.
What he's saying is along the lines of saying that body armour for infantrymen is a bad idea because it can still be penetrated. But that'd only be a good argument if the guys wearing it were supposed to just outright walk up to the enemy without weapons, and physically take their weapons away from them. That's just not how it works, it's not a substitute for older methods and equipment, but rather to decrease risks.