I'd always heard of Bird as a bad defender, even from worshipers like Bill Simmons, and he's pretty bad man-to-man against anyone athletic, but the dude was a savant help-wise as much as he is on offense at just knowing where everybody is. Just watching the vid Stoney posted he's constantly popping up out of nowhere at the worst possible time for the Rockets to help, poke away at the ball or add an extra contest to a shot. Or even just to secure a board. Since there's no danger of a team rotating the ball around the arc to the open three pointer he can dominate whole stretches without shooting just from doing this and from his passing.
McHale's similarly not great athletically but is super smart, doesn't fall for almost anything and has great timing. So he's not killing their defense either despite his obvious flaws.
I watched some old games or parts of them on YouTube a while back and all the bad long twos definitely stood out. And it's not like good shooters taking them it's almost everybody. I remember Kevin Duckworth out there jacking up bricks on multiple possessions as Clyde looks like he's about to strangle the guy. Watched a Denver-Lakers game where everybody spent most of the first two quarters just running back and forth taking semi-open 18-20 footers. Then finally Magic starts curating inside to Kareem and Worthy and they go on like a 14-0 run the Nuggets never recover from.
It's also funny when you come across a game where a dude is taking a bunch of triples and making them, like Michael Adams was an early three point bomber I found quite a few games of, and nobody seems to know what to do about it. Dude's hit like five threes in an era when teams don't hit that many and they're still guarding him for the drive or giving no effort to watch him closely as he jogs around a screen. Even he stopped taking the three and started going inside though as the game was getting towards the end like it was uncouth to be killing whoever from out there.