some speakers do better with some musical genres than others because their strengths and weaknesses are more befitting and tolerated with certain kinds of music
example:
klipsches tektons zus - these are ’lively’ brash sounding speakers, excel with drum snaps, forward presentation, not the most refined, not the best at imaging - so they work well with electronic music, rock, ’party tunes’ - they are good with the beat, impact, energizing, in-your-face sound which is the essence and goodness of that kind of music
If a speaker is 'brash' at some point you'll eventually tire of that even with electronia or rock. What's being ignored is that there are some excellent recordings in these genres that easily reveal speaker problems. Once revealed you'll always hear it and it won't matter the genre!
(here are some examples:
'Paranoid' by Black Sabbath; get the white label Vertigo pressing to really hear what that recording is about
'Mystical Experiences' by The Infinity Project big bass, lots of fun details hidden in the mix; get the Blue Room Released LP pressing if you can find it)
The idea that a certain speaker can favor a certain genre is the biggest myth in audio. If its good at rock but sucks at classical, you'll find that if you play enough rock recordings it actually sucks at rock too.