I think this is a matter of coincidence. The lock and chat bubble leads itself to a familiar look. I'm pretty sure you aren't the first person to think of such a concept, and neither are we.
Besides, the icon was made by an anonymous person so it's not really like we can blame anyone.
The hidden service mirror has been stripped of Piwik tracking, and forms of Javascript, and soon we'll label outbound links.
i2p support will also follow soon.
Tox main site: http://kdzzxucnh4fyovxg.onion/
Tox developer documentation: http://kdzzxucnh4fyovxg.onion/docs/
Tox wiki: http://kdzzxucnh4fyovxg.onion/wiki