Proposed Federal censorship régulations may prohibit us from giving you information about the possibility of calling this function. We would be required to say

Proposed Federal censorship régulations may prohibit us from giving you information about the possibility of calling this function. We would be required to say that this is not an acceptable way of terminating a program. I don't get the joke; I think I'm missing some context since I'm not from the US. Can you explain it?