I see a few issues with your argument. Just because something has underlying social factors doesn't mean that it shouldn't also be treated with drugs and therapy. The latest wave of psychedelic research is not simply pushing a prescription drug; all of the research on MDMA, psilocybin, etc. is finding that these drugs work within a clinical setting paired with therapy. Also, I wasn't able to find a source saying that PTSD is less prevalent outside of the US. I found one study [1] that says that treatment seeking is higher in high-income countries. However, this doesn't imply that the US has higher rates than Europe, for example. It could also be the case that the disorder is just as prevalent or higher in lower income populations without access to mental healthcare.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034513/