While the petitions themselves are conversation worthy, the potential for controversy before a response is high and could deter the White house from answering a petition without 100,000 signatures.
However, the public responses to a petition should be fair ground. Language censorship and public moderators on the responses could be used to keep things civil, while maintaining our ability to be heard and further discuss the important topics.
At the very least, give the creator of the petition the ability to publicly respond to his response. If the white house deems it worthy of a response, haven't they earned it?