Boy do I hate that phrase. It's absolutely incorrect from a neuroscience perspective. Words can in fact hurt you, and, depending on circumstances, cause long term psychological damage. Here's a place to start to learn more if you want: https://www.td.org/insights/the-neuroscience-of-reward-and-t...
Hurt has acquired multiple meanings. The phrase you hate refers to "hurt" of the bone-breaking variety. To me, that makes it clear. But maybe it's confusing.
Fun! Yup, metaphors can be great and apt. We can extend the word “harm” to any desired degree, and find motivations like this.
Then if we bring the new variable value (harm includes psychological harm) back to an older equation (words can never harm me), we can derive anything (the phrase is now wrong).
There is no logic police to stop us from doing this when it’s useful.
Another example: “beer will get me drunk”. I hate this phrase, so let’s fix it.
First, I can say that being “drunk” is similar to being “in love”. It has many similarities, after all, and I think those justify equivalence. From there, I can say that being “in love” is after all very similar to being “loved”.
Bringing it back, my statement is now “beer will get me loved”. It’s the clever hack underpinning many great nights.
It may well be harmful, but your reasoning seems spurious. It would imply that "marijuana can be so harmful that is made illegal almost everywhere in the world".