Image from 1994 film Forrest Gump
I have found that the number one key to significantly reducing stress in your life is to stop caring about other peoples opinions. Whether it's about politics, religion, life, whatever it is, stop caring what other people think about those things. You will immediately feel the release of tension and stress in your life.
Everywhere you look on television and the internet celebrities and other public figures are attacked left and right for expressing unpopular opinions. For example, a couple of years back Phil Robertson of Duck Dynasty expressed his opinion of homosexuality which was not even surprising considering his Christian background yet people lost their marbles over it. Why did they care, because he was on TV? Does his opinion matter more because he's a celebrity?
It almost seems like we are slowly trying to implement thought control, if someone expresses an unpopular or not so PC opinion said person is virtually crucified although his/her thoughts are shared by many others. People spend so much time trying to make other people think the way they do but it will never happen because we as a species will always be stubborn jackasses. Political-correctness is in fact an anti-freedom of speech movement that turns people on each other like rabid wolves.
99% of all war and gun violence could be prevented if people didn't care so much about other peoples thoughts and opinions. Just freaking love each other and leave politics and religious arguments where they belong. When it comes to opinions, don't trust any but your own. When it comes to your beliefs, accept nothing less than the absolute truth.