This topic is a little more complex and confusing than I expected. I'm tempted to change the title to "Which fallacy blames the victims rather than their oppressors?" But I'm not sure if that's a better title or something completely different.
See my clarification at the end of this post.
Imagine a political activist who says something that's true but not politically correct. The government responds by passing a law making it illegal to say what he said.
Instead of criticizing the government, some people tell the activist, "Thanks a lot. If you had kept your mouth shut, we wouldn't have lost more of our rights."
To put it another way, they're saying that we have the right to do certain things...as long as we don't actually do them.
What kind of fallacy is this, if any?
EDIT
This is not a question about the definition or judgment of right and wrong, nor is it about moral relativism.
Just as some philosophers believe in a Christian god, so are there some philosophers who believe in right and wrong, many of whom further believe that murder and pedophilia are immoral.
I want to frame my question from just such a perspective: Let's imagine a society where murder and pedophilia are widely regarded as both immoral and illegal. However, there are members of this community who are murderers and/or pedophiles. Some of these people are very powerful, influential and maybe even respected.
So when one of these individuals is exposed as a criminal, members of the community may attack the whistle-blower, for a number of reasons. Some of the attacks come from propagandists or friends of the accused who simply do what all propagandists do. Other attacks come from seemingly ordinary citizens who simply get upset when someone rocks the boat or says things that they think casts the community in a bad light.
Here's a hypothetical example:
Imagine a member of the community who criticizes a judge who has been exposed as a pedophile. The government retaliates by passing a law making it illegal to criticize pedophile judges.
Rather than rally behind the pedophile judge's victims, the general public rallies behind the judge and government, blaming the obviously disgusting law on the whistle-blower. A newspaper headline reads "Self-appointed whistle-blower responsible for law shielding pedophiles."
This can obviously be classified as propaganda, but can we further identify it as a particular kind of fallacy?