But comprehensions are also a functional idiom.
Do not confuse FP with declarative programming or with laziness. FP often implies declarative APIs and laziness but not vice-versa.
(expr for item in iterable if cond) is more or less another way to spell map(lambda item: expr, filter(lambda item: cond, iterable)), except readable.
You could define "functional programming" to absolutely require referential transparency, but that's not what the rest of the thread is doing.
Obviously it's ultimately the same thing either way, but that's the lineage (SETL -> ABC -> Python).
https://docs.python.org/3/howto/functional.html#generator-ex... claims Python borrowed them from Haskell, but the ABC link seems more likely.
As I recall, Python did get them from Haskell, which in turn got them from Miranda, which got them from KRC. Before that it gets fuzzy, but it's likely that SETL was eventually at the root of it.