Yes, science does detect planets in the way you described.   You seem to be arguing that this methodology is seriously flawed, and that's there's doubt among astronomers if the Trappist planets are actually planets.    

Which astronomers hold that opinion?   I can't find any.

Along with that, you wrote that "astrophysicists think there is just as much chance [these are really planets] that the universe as we experience it is a hologram."

Again, I'm not finding any statements by scientists that the Trappist claim is as likely, or unlikely, as the hologram universe  theory.