Could you please taboo "oppression" and its synonyms? You seem to be using it as a sort of discrimination/cognitive bias affair which doesn't seem to fit colloquial use of oppression.

Oppression in common usage appears to signify systematic stereotyping with a net negative effect for the population group in question, or specific behaviors associated with oppression of a group, in which case neither males nor white males are oppressed, even though there are indubitably cases where discrimination and cognitive biases turn out negatively for specific subgroups (such as male nurses, cuckolds, divorcees, etc.)

"Objectification" is another such concept. We know that it's yet another piece of jargon for a bad thing that men do to women. But we don't really know what it and why it's wrong, nor it is demarcated from ethical forms of imagery.

Objectification is a well-defined and experimentally verified to exist phenomenon by which women in western society at least judge themselves by the impression others have of their physical bodies, which correlates, amongst other things, to eating disorders.

While the connection between sexual imagery and objectification is less easily findable with google scholar, here is a study which correlates violence in watched pornography with short-term aggressive behavior.

With this definition of objectification - the identification of women and their physical appearance (9 on the list) - it is obvious that the Playboy magazine is an example of an act of objectification, while people playing in mud is not: the playboy magazine serves to display a prime specimen of the female body, while the other image serves to display a prime specimen of people playing in mud.

Hence, the only assumption we need to make is that playboy magazines cause the same objectification which causes psychological damage to women is that objectifying specific women or seeing women being objectified causes the objectification of other women, which frankly does not seem unbelievable because it's basic "monkey see, monkey do".

It should also be noted that every last posited "defining characteristic" is directly implied by characteristic #9. #8 through specification and the others by negative phrasing, and that #9 is in fact the apparent scientific definition of the concept. So while the other characteristics increase the probability of objectification, they don't guarantee it.

Of course, social constructionism isn't the only objection to feminism. See this post for some other books that critique feminism. Keep in mind that not all feminists make these sorts of errors, but particular groups of feminists do, and don't get sufficiently called on it.

One last thing: Your statement that not all feminists are social constructivists implies that the truth value of social constructivism doesn't affect the truth value of feminism, but rather the truth value of whatever those feminists do believe that makes them social constructivists, assuming there are rational feminists who are not social constructivists.

PS: Hi, I'm new here. Please be patient with me if I'm in error.