Spread is just one social effect. I think the GP meant that there are plenty of other civic motivations, like not overloading medical institutions and minimizing the extent to which society needs to be halted to prevent particularly harmful spread.

By all means I would encourage everyone eligible to get vaccinated. But there was never any valid reason to halt society in the first place, so your comment is a non sequitur.

Even before the COVID-19 pandemic, it was routine for medical institutions to be overwhelmed by respiratory viruses. We didn't halt society, we just accepted the consequences and moved on.

https://time.com/5107984/hospitals-handling-burden-flu-patie...

https://peterattiamd.com/covid-19-current-state-omicron/

There's a significant difference in kind between "a nasty cold or flu season" and the excess mortality rate we've seen during COVID, particularly earlier in the pandemic[1].

There's no non sequitur here: getting vaccinated reduces every demographic's risk of serious illness (even when serious illness is not especially likely!), which in turn reduces the burden on healthcare institutions. That is a good civic reason to get vaccinated that has nothing to do with transmission.

[1]: https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htm

"there was never any valid reason to halt society in the first place"

Look whatever you think about anything full hospitals everywhere and people in Spain being left for dead in old folks homes were definitely real things - I am not sure about your definition of "halt society" here but policy choices that reduced social contact in indoor spaces was absolutely required. You just can't rewrite history if that is what you are trying to imply.