That’s talking about herd immunity from vaccines. OP is talking about herd immunity from natural infection. So your links don’t invalidate the point, considering Israel research just proved that natural immunity is 13x more effective against Delta than Pfizer mRNA
......? Herd immunity is herd immunity. It doesn't matter what caused it.
Natural immunity is great, but most people clearly don't have and won't get natural immunity. Having had COVID-19 already also does not make you later immune, to any variant. You can get it again and spread it again. https://health.clevelandclinic.org/can-you-get-covid-19-more...
Here’s why herd immunity from Covid is ‘mythical’ with the delta variant https://www.cnbc.com/2021/08/12/herd-immunity-is-mythical-wi...
The developer of the AstraZeneca shot says the Delta variant has made herd immunity impossible because vaccinated people can still transmit the virus https://www.businessinsider.com/delta-variant-made-herd-immu...