Yeah that stuck out to me, too. The fucking kernel is written in C. 90% or more of the networking stack is written in C. Graphics APIs are written in C. Compilers, databases, firmwares, older video games,
everything.
C is not known for vulnerabilities, it simply makes it easy to shoot yourself in the foot. The tooling exists to improve code safety, but generally if you don't do anything crazy, nothing crazy happens.
Lasers, chainsaws and pressure washers are all easy to hurt one's self with but I wouldn't say they're known for creating injuries. It's more like people are stupid enough to hurt themselves with tools regularly.
It's not hard to check a value before dereferencing or freeing it. It's hard to remember to do it.