[SauronOfMordor]

In reality, there is no legitimate age of consent for intrinsic evils like pornography and abortion. Intrinsic evils should be criminalized. The only subject for debate are the penalties that should be applied.

In the real world, a government with the power to criminalize porn as "intrinsicly evil" also has to power to punish "criticism of homosexuality" or "racially offiensive speech" or "general politically-incorrect attitudes" as being "intrinsicly evil".

Be careful what powers you choose to give government, particularly at a time when those who oppose your value system are the ones with the political power

[Long Cut]

Both the extreme Right and extreme Left have little tolerance for individual Liberty which does not turn out to their preference. Both would happily use the hammer of government to beat everyone into their own preferred shape.

[Aquinasfan]

Be careful what powers you choose to give government, particularly at a time when those who oppose your value system are the ones with the political power

That's the slippery slope fallacy. Legislators should work to create the best, most prudent body of laws that they can. They shouldn't override this objective because of a feared future, hypothetical situation.