Author of the post. I think that this is exactly right. I don't know what motivated the companies to put that policy in place (they just told us that they had this preference). But I can speculate. There is an epidemic of interest in ML. Four out of 5 college grads we speak to list it as an interest. I think that interest has grown to the point where it's no longer any kind of signal about technical strength, and perhaps a signal that the candidates will not be flexible about what they work on.
What about we academic programmers who have real experience and knowledge about ML. Is that still a negative sign? Or does the academic part make it worse :)