I don't think "critical thinking" is the point here. Because first you need to know that such modifications CAN be done. And not everybody knows what can be retouched with PS or programs. So yeah, if you see some super-model on a magazine cover, and you don't know PS can edit photos easily, it would be not that immediate to think "hey maybe that's not real!".
As an extreme example: would you ever checked 20 years ago a newspaper text to know if it was generated by an AI or by a human? Obviously no, because you didn't know of any AI that could do that.
I think I made my point badly because I also agree.
I am lamenting that teenagers were, in this day and age, surprised at what can be done with Photoshop. And that let loose on the appropriate software were surprised at what can be altered and how easily.
My point is suggesting this may be so because people have not been taught how to think for themselves and accept things (in this case female images) 'as is', without a hint of curiosity. It is also a problem but at the other end of the stick, with many young people I work with considering Wikipedia to be 100% full of misinformation and fake news.
There is a secondary aspect of becoming aware that society has agreed on beauty standards (different for different societies) and PS being used as a means to adhere to these standards.
Namely, critical thinking?