There may be truth to this....but when I had other breeds they did go boody.I was told this about the chickens here when I took over their care. There have been various breeds here over the years sourced from the UK, France and locally. Until I took over their care that had not been a single incident of a hen going broody.
I spoke to a few of the local chicken keepers here and the general consensus was the breeding out of such a basic instinct was complete nonsense.
I was told it's about how you keep them.
So, I listened to the people here who have been keeping chickens for centuries. It did take a bit of time but now every hen that lays eggs will go broody.
What reinforces the notion that the broodiness has not been bred out of many breeds is what happens when for whatever reasons those breeds that are supposedly bred to such a point go feral. There are plenty of reports of some of the American standard breeds reproducing and able to keep a maintain a thriving colony.
Just my own experience though. Nothing can be proven from that lol!