Double-oops, I was all wrong, it’s just that we introduced a bug and for an hour or so there, SELFDESTRUCT datapoints were just always self-destructing. It was impossible to add them at all. 
UPDATE: Ok, the bug is fixed but it’s so embarrassing. The Chesterton’s fence should not in fact have been ripped out! New status quo is that everything works as advertised except we currently still have the special case that SELFDESTRUCT datapoints do not cause other SELFDESTRUCT datapoints to self-destruct.