not changing working code to prevent issues is unsafe.
we can go in circles all day with blanket statements that are all true. but we have ample evidence that even if we think some real-world C code is safe, it is often not because humans are extremely bad at writing safe C.
sometimes it's worth preventing that more strongly, sometimes it's not, evidently they think that software that a truly gigantic amount of humans and machines use is an area where it's worth the cost.
believing that rewriting to rust will make code safe is unsafe) Of course it will be safer, but not safe. Safety is a marketing feature of rust and no more. But a lot of people really believe in it and will be zealously trying to prove that rust is safe.