People disagree about meaningful and trivial matters on a daily basis. Sometimes you know if you speak your mind you will upset someone. However, you often must express your opinion even if you know others will disagree. By choosing your words carefully you can avoid a long-term offense.
Ways you can go about it are;
1: Ask people about their perspective
2: Put yourself in their shoes
3: control your words and body language
4: be polite in your responses
. And so on