This legislation goes against freedom of speech and artistic expression. 'Virtual child pornography' is just that – it does not involve real children directly (as in a photograph) or indirectly (as in a pseudo-photograph), both of which are illegal under other, earlier legislation. It is a completely victimless crime, unless you count the person being accused of it!
It is also very confusingly worded and subjective, such as the definition of a 'child'. How do you differentiate, for example, between a cartoon picture of a legal 18 year old and an illegal 17 year old?
Why is this idea important?
Removing this legislation is important for the following reasons:
It would restore freedom of artistic expression
It is surely a safer, preferable outlet for paedophilia than any involving real children
It would be one less victimless crime adding strain to the criminal justice system