"She attempted to play the player rather than the ball".

17:35 Jan 8, 2023 

Thank you to all who contributed, especially to philgoddard and Emmanuella. The problem was solved with your help.

09:35 Jan 8, 2023 

Yeah, it’s just A knocking B for an ad hominem attack

06:50 Jan 8, 2023 

SM is social media in this context.
I think you are right, our expression was probably used in that somewhat oblique way. A was defending themseives from B's comment by saying that the point of their post had been Ms XXX's action, whereas B was criticising A for HER reaction. This would fit the definition found by Emmanuella
"To object to someone's argument by attacking them or a facet of their personality instead of the argument itself"
I hadn't realised what the expression was referring to, so my initial context was misleading.
So who do I now give the points to !?

19:34 Jan 7, 2023 

I found the Facebook post (is this your college?), but it looks like these comments have been deleted - perhaps because they were offensive and incomprehensible!

19:23 Jan 7, 2023 

So the remark may be directed at A for the comment about the cave in the Arctic, which I don't understand. I assume SM is something other than sadomasochism. These people are not very good at expressing themselves.

If it's on Facebook, can you ask A what she meant?

17:55 Jan 7, 2023 

For anonymity I have made some unimportant changes.
The student body wrote under a picture of the don "Ms XXX is a woman of her word - and to prove it, she's given us a taster of her promise (...) You can join in and make sure she has to fully submerge by making a gift here:"
A (my critical person) posted next:" In the olden days a don (i.e. Ms XXX) was a dignified woman who didn’t indulge in cheap stunts."
B(another person replying to A ): "Ms A, This would seem to be your initial foray into SM - do you perchance live in a cave in the Arctic?"
A's reply to B: "Well, thanks for proving how standards have fallen. In my day anyone who attempted to play the player rather than the ball would have (metaphorically) had her skin removed by her tutor."
B (to A): "Thanks for proving my point."

17:18 Jan 7, 2023 

Your header says "she attempted", implying the don, but the actual quote is "anyone who attempted". This could be a criticism of the previous people praising her.

Also, how do you know that the commenter thought this was undignified? Is this additional context that we don't know about?

I agree with Mark that the idiom is misapplied, but I don't think we can speculate on the intended meaning. It simply doesn't make sense to me.

You say people replied to this comment. What did they say? It would still help to see what everyone said, rather than a selective paraphrase.

17:14 Jan 7, 2023 

The comment is strange and the idiom is misapplied. However, the intended objection is probably to that fact that the don is being talked up, rather than the cause he/she is supporting.

16:56 Jan 7, 2023 

Thanks for your input! There was a post consisting of a photo of the don in question pretending to dive into the river and urging users to donate to the good cause. Some people wrote in in appreciation of what the don was doing. Then the person I am quoting wrote: "In my day, anyone who attempted to play the player rather than the ball would have (metaphorically) had her skin removed by her tutor." People replied to that of course, but I don't think it would be of help here.

16:48 Jan 7, 2023 

16:35 Jan 7, 2023 

Thanks.
It could mean indulging in personal criticism rather than judging people by their actions.