This quote hails from the liner notes to this CD: John Adams's Violin Concerto performed by Leila Josefowicz, David Robertson of St. Louis Symphony Orchestra. Alice Miller Cotter has a BA in Music (Berkeley), PhD in Musicology (Princeton).
I'm afraid that this question has nothing/little to do with linguistics but rather with philosophy. In particular, this question must be understood in the following context where Ricoeur's (famous?) distinction between two kinds of identity in relation to selfhood is summarized: see Section 5. Narrative Identity and the Turn to Selfhood in https://plato.stanford.edu/entries/ricoeur/ Cf. "Idem identity is the identity of something that is always the same which never changes, ipse identity is sameness across and through change".
I cannot see how ipse would indicate change. I would rather say that both idem and ipse indicate sameness, although in a different way.
There might be an argument for the kind of distinction the text is trying to make, but no such argument is provided in what you quote. Therefore, until further proof is provided, I see that as a failed analysis of those Latin words.
Let's ignore the quote in your question for the moment.
The question is can a person, writing in a language other than Latin, take a Latin word - or rather, its sound form, perhaps with - or without- some "semantic load", shall we say - and use it in a language other than Latin, and use in a sense that they deem necessary?
The answer is - yes. Examples galore.
Does it have any bearing on Latin? The answer is no.
Now, back to nos moutons (the quote in your question. Unfortunately, Ricoeur’s philosophical distinction is presented there as a fact of Latin lexicology (vocabulary studies). This is certainly not true and imho should be rewritten, with a reference to Ricoeur’s philosophy, not the Latin language.