Why do many of todays parents say rock music is discordant?

It is possible some older individuals, including a portion of parents, perceive certain characteristics common to some rock music that way, considering that they grew up in different musical eras. However, music preferences and perceptions are highly subjective, shaped by personal choices, and what sounds discordant to someone might be perceived as pleasing and energetic to another.

In some cases, people might associate rock music with loudness, raw sounds, distorted guitar work, aggressive vocals and unconventional beats of certain sub-genres that might seem disharmonious to their ears while still being attractive to the fans of those very elements that challenge musical convention.

Overall, labeling contemporary or general rock music as inherently "discordant" might reflect some individuals' tastes but doesn't capture the entire picture, rock encompasses many sounds across the genre spanning decades.