Now, I've seen this kind of thing before. Protestants don't share these devotional traditions, so manufacturers will block that part of the mold that has the heart in it and run some articles that they can sell in the Protestant market. It's cheaper than making a new mold for a new product. And you get a perfectly sellable version of Jesus and Mary pointing at, well, nothing.
I bought these at a Protestant church, so I guess there is a market for them. But when I was growing up Southern Baptist, what religious art we had tended to be more like these:
You had your classic Jesus profile with subtle halo.
You had your Good Shepherd.
You had your Jesus at the door. (Now I've got cheesy Paul McCartney songs running through my head.)
You had your praying hands. (It's fascinating how many pics of tattoos come up in a Google image search for this one.)
And, other than a Ten Commandments plaque or a pic of the Bible, that was about it. Oh, there were a few homes with a Crucifixion scene or a Last Supper, but no one that I knew anyway had "Protestant-safe" versions of the Hearts anywhere. Wonder when someone got the idea to start trying that. I mean, I bought it at a sale, so someone else obviously got it somewhere. Still, the idea of a non-Catholic home with any kind of an image of Mary--heartless or not--just strikes me as odd. My grandmother would have had none of that, let me tell you.
One of the things that appealed to me about Catholic themes in religious art is a combination of the drama and the kitsch involved. The religious art I grew up with just seemed so plain to me in comparison with pictures of the Twin Hearts.
Now, I know that life doesn't always fall into neat little categories. In reality, there were and are plenty of Catholic homes that have copies or versions of everything I've listed above. There's nothing about any of those images that brands them as "belonging" to any particular kind of church. I just tend to think of them as "Protestant" because that's what I grew up with and how I was raised.
Take another look at my little statues:
With no heart showing, but hands still kind of clutching their chests, doesn't it kind of look like this is what they're thinking?