Right. It seems to me that part of the reason that some (not all) Protestants tend to downgrade Mary comes from their embrace of the Calvinist, “all men are wholly degraded” viewpoint. IOW, they don’t want to recognize any human being for anything whatsoever; either the human is ‘predestined’ to follow God and therefore saved but it’s all totally God and the human just follows along, or the human is destined to reject God (although it seems in THAT case it’s all the human’s fault, except if he’s predestined that implies God choose not to save him). To them, Mary was a ‘vessel’ which God used (just as He would with any of us weak totally depraved and sinful slobs), and any ‘temporary glory’ she got was from holding Christ in her. Once He was born, she is (to them) of no account whatsoever, and even her bearing Christ was because God ‘told her to’, no glory to her and not even any chance she agreed of her own ‘free will.’
I don’t agree with this at all but thankfully I’m a Catholic and not a Calvinist. I always feel sorry for them because I find their theology frankly ‘despairing’ at best and derogatory at worst.