Not true, Water boils @ 212F but can increase beyond that within reason. I would say 4F is within reason.
There is a limit to how high a temp can be reached with an open top boil. What that is IDK and I am sure it depends on a lot of different factors but I know it is not high enough to sterilize anything. For that you need to increase pressure with an autoclave or pressure cooker w/ 15# weight.
“I'm not drunk, I'm from Wisconsin.”
We have been out drinking your state since 1848!