Mark Zuckerberg
 admits using hurricane-ravaged Puerto Rico as the backdrop to roll out Facebook's new 360-degree virtual reality technology ... was a super tone-deaf idea. No duh.
Zuckerberg issued an apology for the demonstration he and other FB staffers pulled off on Tuesday. The technology is, no doubt, cool -- using VR to drop your friends into your home, your vacation ... or maybe even your decimated homeland ... in the case of millions of Puerto Ricans.
The video is stunning -- make sure you wait for the high-five between Mark and his social media honcho, Rachel.
Tone-deaf is a HUGE understatement.