Some people have a heter to listen to music during sefira because it’s too hard for them to be without music for so long. In that case, it’s better to listen to acapella (that’s the psak I got).
Regarding the poster who compared it to someone in aveilus, l”a, I know a girl whose mother was nifter and it was really hard for her to be without music (I suspect she suffered from depression or something similar, which apparently is true of a very large portion of the population nowadays). Her Rav told her that she only had to refrain from listening to goyish music (which apparently she normally listened to).
Even without special heteirim, there are many opinions regarding what one is and is not allowed to listen to during sefira, so certainly no one should be judging anyone else (unless they are holding a public concert with live music, and then maybe you should just assume that they don’t know better).