You can talk about politics, because it affects us all and impacts on our daily lives... as long as it is rational (identify the problem you have and give reasonable alternatives that the politicians are ignoring for self-serving reasons)... and if we don't talk about it, we the "common people" won't fully understand the process and specifics enough to improve things or get enough people support it (without ending up with a mob mentality of misguided opinions).
The rules just recommend not talking about political parties, or any other organisation that people grow up with or long-term loyalty to, as it can lead to dismissing or excusing poor decisions that are proven issues against that organisation... and can prompt others to target those people of a particular organisation for fun or sport.
Keeping it rational has a better chance of drawing in people from those organisations than making fun of them.