I didn't downvote your comment, but I hold your sentiment in low esteem.

We don't stress over this for the same reason we don't stress over strlen-style errors. They're considered part of the basic education for the language. If someone does do this, they are operating below the expected standard for the language.

There is only so much a language and environment can be expected to do for you. Your understanding of trivial concepts like, "Loading code from untrusted sources is dangerous" is not an unreasonable bar to set. It is only an "issue" if you are fundamentally misinformed about writing software in interpreted environments.