You still need to know how to play an instrument (the computer, electronic keyboard, etc) in the case of electronic music.
When you strike a key on a piano, a hammer hits a string which vibrates and creates a sound in the analog domain which you can hear.
With an electric guitar, the sound from plucking a string is picked up by a transducer where it is converted into an analog electric signal, which is then made louder/altered by an amplifier and converted back into the acoustic domain by a loudspeaker.
With a keyboard/sampler/computer, a key on a keyboard (for example) is hit which is a mechanical analog action that in converted into a digital impulse that triggers a digital sound/sample which is then converted back to an analogue electical signal that is amplified and fed to a loudspeaker to be converted into the analogue acoustic domain, which the human ear can detect.
Note the progression in technology which enable new styles of music.
The electronic keyboard is basically the same as a piano, except with a piano you are stuck with a piano, and with the computer you can make basically any sound you want.
Let's face it, the piano is an ancient instrument that is still around today because it has a pleasant sound to people mainly due to conditioning from a young age in the same way that people believe in various religions depending on how they were brought up and which part of the world they live. I bet if you heard a piano for the first time in your life today you would not think it was anything special. Though you might be impressed by the technical ability of the player.
A lot of electronic music uses "new" synthesized sounds which are unfamiliar to a lot of people, and many people simply cannot handle "new" and unfamiliar.
All throughout history old people are always complaining that the music they listen to was better than the new stuff. They just have failed to adapt.
PS there is no such thing as good or bad music as there is no objective metric to measure how "good" music is. That's why music charts are based on sales and downloads, as there doesn't seem to be any better method of assessing music quality due to subjectivity of each listener.
