The reason why it's a loss of down is because it's illegal touching by an illegible receiver downfield, which is basically two penalties in one. An ineligible receiver downfield penalty by itself or an illegal touching penalty by itself is not a loss of down, but the two together result in a loss of down.

I was really confused by that at the Sam Houston game because they just said that it was an ineligible receiver downfield and didn't add that it was illegal touching, so I was freaking out that it was a loss of down. The later in the game Sam Houston had an ineligible receiver downfield and I yelled at the refs because they didn't add the loss of down. That was the right call though as the Sam Houston ineligible receiver didn't touch the ball.