How was he lying to the public? He said this in 2020 when the R0 (spread factor) for the original strain of Covid was around 2. The most recent strain of COVID, omicron, has a R0 of around 19. The calculation for herd immunity is based on the R0 value of the strain in question. With a R0 of 20 you have to get to like 95%+ to get herd immunity.