screamo is usually regarded as a different thing than death metal, i think you may just mean deathcore. and to each their own, from a metal listener it’s definitely about the anger but also it’s just pleasant to listen to. the heavy rhythmic elements are really enjoyable and satisfying to listen to. when it comes to the vocals, it’s kinda within the style to sound like that, the vocals are treated as an instrument like the guitars or drums are and usually you aren’t supposed to understand the lyrics anyways.