Maybe I’m reading too much into it, but what strikes me, is that it sounds like this JW ‘witness’ intended it as a slieght, as if Mary remaining Jewish–as if being Jewish–was somehow, somethig negative.
Again, maybe I’m reading too much into the question. Maybe I presume too much historical background (as laid out by DF above)–but I get the impression that he left you with this question to ponder, with the idea that you would be turned off at the notion that Mary was, and (naturally) remained, Jewish.
I would have asked—what exactly are you meaning with that question? Why wouldn’t she have remained Jewish? Did Jesus Christ curse the Jews? …or did He say “…forgive them father, for they know not what they do?” Would you have preferred that He had not forgiven his executioners? (and therefore, not us?).
IMO, this is just another silly ‘apologetic’–another veiled attack on the Virgin mother, that feeds into this natural protestant aversion to all things Mary.
—(and yes, I know protestants proper seek to disown the JW’s, and the JW’s proudly disown protestants–but the JW origin basically follows the protestant path, of rejecting the Church that Christ founded, in favor of [supposedly] following the Bible–of course, to the Catholic mind, that is a contradiction–you cannot pretend to follow the Bible, while simulteneusly rejecting the Church of which it speaks, and to whom it was written, and assembled–and frankly, by which it was written and assembled–at least wrt the NT that is).