We are told we can talk about the weather but not about religion or politics.

Weather is beyond our control, but politics and religion are not. I believe the people who have cemented their power over thousands of years do not want us to challenge their power, so we are told it's impolite to talk about the ways in which they exert their power.

But the only things we SHOULD be discussing of a general nature are religion and politics, because we can affect change there...unlike the weather.