It was a bad idea in the first place (born from a good place, but not thought through). Rainbow armband, great. Video of support, great. You don't need every player to openly participate in something that in Mazraouis situation, could be a lose lose either way given where he is from. So that's why it was scrapped. Either the others wear it and he gets shit on, or nobody wears it and they hoped nobody would find out about the possible idea. The idea was leaked, so he gets shit on anyway.
We are still wearing the rainbow armband which is the standard move of support, just not doing the "above and beyond" move. It's sloppy, but IMO isn't the club dismissing it. Just choosing to protect their player and looking for an alternative way to do it.
As I mentioned before... Liverpool and Salah have never received criticism for something like this because they've just managed it well and have never asked every member of their team to participate in it. It was always the captain as with most clubs (including us).