Parents shouldn't think and assume all cartoons, video games, etc. are harmless fun.
It is not much of a problem as it was before, as most parents of young children today grew up playing video games. The kids that played games when Conker's Bad Fur Day was released in 2001 are now parents themselves.
Plus, there are parental controls on numerous devices and apps so that children don't access any mature content. Netflix and YouTube, for example, have accounts that only have kid-friendly content. It is not 100% guaranteed to stop curious children from going past the controls, but it works most of the time.
As an aside, they stopped making audio cassette tapes years ago. The last time there was a major cassette tape release was in 2014, when Disney released the soundtrack for The Guardians of the Galaxy on tape. I have the tape, but I haven't been able to play it due to not having a tape player.