Individual efforts become a defensive key when you want to have a good team defense. As a coach you allways want to keep everything under control, set rules, make your players follow those rules... But at the same time you ask them to be aggresive, to make decisions, to read the game... And sometimes that means giving them freedom to break the rules.
In the video we can see a quite common offensive set used by the Philadelphia 76ers (and many other teams all around the globe) and even if we don't really know what's the defensive rule, quite often the ball's opposite side defender will be responsible for helps. We could say the most frequent help when defending that set would come from the free throw line defender, who would take a couple of steps back to avoid the pass to the curl. Instead, it is the low post defender (from ball side), Kevin Garnett, who reads the situation and thanks to his athleticism and awareness steals the pass.
The main idea is that even if we have clear defensive rules (and one of those is often "never help from ball side") sometimes, with some players, in some teams, a freedom degree when reading the game will make your team better. That's why I dare giving an advice: try not to use the words "allways" and "never" very often.