Hmmm...
It is more of an American stereotype but there is some truth to it and some rather tragic consequences - one non/weak swimmer getting into trouble and other non/weak swimmers trying to help can be a disaster:
https://www.bbc.co.uk/news/world-us-canada-11172054
When 15-year-old DeKendrix Warner accidentally stepped into deeper water while wading in the Red River in Shreveport, he panicked.
JaTavious Warner, 17, Takeitha Warner, 13, JaMarcus Warner, 14, Litrelle Stewart, 18, Latevin Stewart, 15, and LaDarius Stewart, 17, rushed to help him and each other.
None of them could swim. All six drowned. DeKendrix was rescued by a passer-by.