you mean: for any reason which violates the principle of free speech
now we have to make sure you understand what free speech means:
1. brain dead "anything that can ever be said is ok and is fair game"
2. free speech as limited by forms of speech that impinge on other basic freedoms (threats to murder, child porn, the proverbial shout of "fire" in a crowded theatre, etc.)
all freedoms exist in tension with other freedoms. your freedom is most frequently violated by morons around you, not big bad evil government out to destroy your freedom for shits and giggles like a cartoon villain (this doesn't excuse government free speech violations, it only puts it in context of the topic in this comment)
examples of freedoms in tension: my freedom to listen at music at 2 AM, your freedom to get a good night's sleep. your freedom to drive as fast as you want, my freedom not to die in a car crash. your freedom to take a piss right now, my freedom to grow petunias in my front yard
so now, once we have graduated from the airhead immature teenaged definition of freedom "i can do whatever the fuck i want, be damned the consequences," and we understand that true freedom means "i can do whatever the fuck i want, as long as i don't limit other people's freedoms" then we have a logically coherent and valid definition of free speech: speech which does not hurt other people's freedoms (incitement to murder, child porn, "fire" in theatre, etc.)
meanwhile, if you think something like child porn should be allowed, you simply do not understand what freedom or free speech is
you really don't. i am being 100% serious
if you think something like child porn should be allowed, you're playing with a simpleton's teenaged immature definition of freedom that is invalid and only marks you as a clueless idiot or a malicious douchebag