Well it does make the developer try harder to have a vulnerability. You can't just forget to bound check an array indexing, you need to actually take instructio

Well it does make the developer try harder to have a vulnerability. You can't just forget to bound check an array indexing, you need to actually take instructions from the Internet (e.g. eval, import, or exec in case of fail2ban), but of course the way this happens is usually very indirect (e.g. race condition). No programming language can stop a determined developer from creating a vulnerability, but some languages make the task easier than others.