I would agree that they can pick up on some emotions. Its just that they're not bending over backwards to please you as say a dog might.
I would say the strongest emotion they will sense from you is fear, because we tend to stiffen and clench when we are afraid, confusing the horse.
But if you have Never ridden a horse that you just didn't click with, then you probably just haven't ridden enough horses yet, lol.
I have been lucky enough to have ridden almost 200 different horses. Of those, 2 have actively disliked me. 3 I have shared an incredible bond with. The rest, we got along just fine.
The 2 I had trouble with I rode just the same as the others, with patience, easy hands, yada yada. Didn't make a difference, we just didn't click. They were sour with me, fine with many others. Oh well.
One of my special horses was a jerk with almost everyone else, but an angel for me. I am no horse whisperer or top level rider, we just clicked. Same as you click with or dislike certain people for no concrete reason. It happens.