> Not to say that situation isn't bad, but you can't compare it to C++ because nobody ever thought running untrusted C++ code without some other sandboxing was a good idea.

This is actually kind of a point for the other side. You can sandbox code regardless of what language it's written in. Maybe what we need is not better languages but better sandboxes. Even when code is "trusted", if the developer knows it doesn't need to e.g. write to the filesystem or bind any sockets then it should never do those things and if it does the OS should deny access if not kill it immediately.