You get extra credit if you wiki the origins of both strains
While the origins of both diseases may be similar, COVID-19 is much more infectious. That's why the word "unprecedented" is used.
For example: only in my country (Brazil), since the beginning of the pandemic, there have been, in total, more than 800000 cases of COVID-19, and more than 40000 deaths. Yesterday, there were more than 32000 new cases and more than 1000 new deaths.
Comparatively, SARS had 8098 cases worldwide (at least according to Wikipedia).
I thought they based the lockdown on the death rates which was way scarier in sars1
Did you see that both were started by bats in wuhan