I've had this argument with my (tending towards elderly) parents while introducing them to Netflix. They don't understand rating for enjoyment, and keep rating

I've had this argument with my (tending towards elderly) parents while introducing them to Netflix. They don't understand rating for enjoyment, and keep rating for "quality". They'll watch a show, absolutely hate it, but give it a 4 or 5 star rating because "it was well produced and the camera work was good, but it isn't the sort of thing I personally like to watch". I'm worried about the thumbs up/down, as Netflix has increasingly recommended shows I do not like this year, and I don't think the thumbs solves the "rating for perceived quality" issue. I've been using Movielens for recommendations a lot instead, and it seems more accurate for me... and it has enough stats to show that on their site, most rating is not binary, much closer to a normal curve for average movies or a linear graph on really good movies. (It lets you see the distribution curve on individual movies, and other metrics.)