But, if you want, for fun, you can make your own Triangle shaped floating object, you just need a high voltage power supply, and some common household items.
So perhaps the better question is, why is The Pentagon encouraging the speculation by "confirming" the videos exist? Surely they've concluded the same as the linked OP. I can only assume that The Pentagon is either incompetent or being intentionally misleading.
This theory fails to explain the accompanying details of the incidence. The objects were also observed by Navy personnel and estimated to be hovering above the USS Russell at an elevation of 700ft. Plus the assertion that the US Navy can't differentiate between a star and an aircraft is or is not able to identify a 747 is a reach, especially considering there was an official Navy inquiry into the incidence.
Tyler Rogoway and To The Stars Academy are not happy if this information spreads.