I think the difference is that there are many more terrible (or unprepared, or not qualified) physics teachers in the US than there are chem teachers.
In the school districts near me, I’ve seen many “master teachers” of physics retire and get replaced by rookies. Or worse- get replaced by mid-tenure “science and math” teachers who haven’t taken a physics class since they were in college, and get a couple of weeks of review time over the summer before facing a class of HS students. The districts say that it’s too hard to find qualified physics teachers-- which may be true. And a push after the financial crisis to recruit laid off professionals to teach science and math was only partially successful-- someone can be a very talented engineering project manager who aced physics in college and still be a terrible classroom teacher. A lesson which some districts learned after the fact.
My kids got VERY lucky with a master teacher for AP physics. Virtually everyone got a 4 or 5 (some years it was mostly 5’s). The teacher is now retired and the spunky, energetic and under-prepared replacement has yet to figure out how to teach- even to a highly motivated and well prepared group of kids.