[reductive] The main Am(English) dictionary doesn't bring up the meaning as it seems to have been intended

[Ken Blake]

The dictionary doesn't bring up the meaning as it seems to have been
intended as "too simple" (which is vaguely implied in the dictionary,
but not stated).

https://www.creativebloq.com/news/shot-on-iphone-15
But the bold (and simple) "shot on iPhone" claim is arguably a little
[reductive], as shown by a new behind-the-scenes video from Apple.

Nothing about meaning "too simple" nor is the etymology here.
https://www.merriam-webster.com/dictionary/reductive

But the etymology is here (and which was obvious of course).
"From Medieval Latin reductivus, from reduct-, past participle stem ]of
Latin reducere "lead back, bring back," figuratively "restore, replace"
(see reduce). Related: Reductively."
https://www.etymonline.com/word/reductive

It's only when you get to the Oxford dictionary that the "too simple"
meaning show itself to be the case (as it was likely meant in the article).
https://dictionary.cambridge.org/dictionary/english/reductive
"considering or presenting something in a simple way, especially a way that
is too simple:"