That is an unrelated result, although the confusion is understandable. You refer to a theorem, named after Hawking, that states that in classical general relat

That is an unrelated result, although the confusion is understandable. You refer to a theorem, named after Hawking, that states that in classical general relativity the area of black hole horizons must always increase. The experimental confirmation of this theorem refers to the fact that the total area indeed appears to have increased for the black hole merger event observed by LIGO (which should indeed fall well within the realm of classical general relativity). However, once quantum gravitational effects are taken into account this black hole theorem no longer holds. Indeed, since the real world should be quantum, it is expected that the area of black holes eventually does decrease: they evaporate by emitting Hawking radiation. This is however purely a theoretical expectation, since these evaporation effects are a loooong way from being observable; evaporation probably only becomes a significant effect on time scales far beyond the current age of the universe. In quantum gravity there are nevertheless plenty of theoretical paradoxes and open questions, and the above article describes some recent progress by the theoreticians in this area.