A lot of people including myself think that some languages sound better than others. French is romantic and sonorous, Italian is elegant and lively. In contrast, German, Arabic and some East-Asian languages are considered unpleasant sounding. Even within a language, some accents or dialects are vulgar, others are charming. Of course, this is all subjective. You can't call music ugly, since some people love that same music, and the same thing happens with languages. 

Views on languages are built on cultural norms and social connotations. We can not tell people that their assumptions are wrong, since again, it is subjective. We can only try to convince people to be open to any language, no matter how rough sounding it is. That is the only way to let people be truly open and aware.