The Hong Kong flu in 1968-69 was also bad (I remember being very ill at age 6). Yet nobody wore masks, the media basically ignored it, we had Woodstock and landed on the Moon.
I was a senior in high school and don’t recall the flu going around that year at all.
Woodstock and the Moon landing were both in August of course, well past the flu season in North America. Our flu season peaks from December to February and is gone by May.
I was on the toilet and puked and sh!t diahrrea at the same time. It was over in about 48 hours.
Woodstock occurred during the middle of the Hong Kong flu. No one was masked or social distanced.