it doesn't. it only works incidentally. The author isn't an EE and has designed a circuit as if an artist (or an AI) drew a picture of what a circuit looks like.
The weird topology voltage divider attenuates the signal. the op-amps buffer the output. The 470R resistors do nothing. The 1k/1k virtual ground does nothing.
The rest of the authors writings smell of /r/iamverysmart