Well what do we mean when we talk about teaching computer science? Most subjects have fairly broad high-level survey style classes freshman year. Even the X-for-majors classes tend to cover huge swaths of the field with a lot of "you'll cover this more in EPS325" hand waving. The purpose is not to lay a foundation of first principles but to make sure you know enough that you can see connections between topics in later classes, that nothing is too surprising, that you understand what you're in for.

For non majors it's usually so you have enough to be "well rounded" or more importantly (with say english or math) you have enough facility in a field that you can use it's tools to further your work in your own field.

Python might not particularly add much over Scheme for the first situation, but if schools wanted to follow Dijkstra's conception of CS students wouldn't end up touching a computer until senior year let alone Scheme|Python|Pascal|Whatevs anyway and Python isn't distinctly worse for explaining bigO and data structures/algorithms (yes recursion support sucks a bit but not so much that you can't teach it to freshman); Python does however aid in the second tremendously because when students leave CS110 152|whatevs they will go back to their primary field and not have to muddle about learning a new language.

Yes Python is fine for teaching the imperative algorithms needed for a graduate to pass his/her Google interview. But computer science and SICP is/was so much more than that. Even if these institutions want to be vocational, typical software development roles do not require recalling famous algorithms, they require glueing code together. To be good at this, you need a sound grounding in abstraction and composition - the mathematics of program construction. Python will not help people learn this.

Chemical engineering is more than P/S electron shells, balancing RedOx reactions and listing at least one property of each column of the period table but that's all the more you're going to get out Chem 1+2.

Yes computer science IS more than that. Which is why a B(S|A) in CS is a 4 year degree. SICP isn't a complete CS education either. That gluing code together is the typical software job is if anything an argument against Scheme/SICP.