hurtloam wrote:
Like how I live my life, my political views etc.
People generally say "What does it matter?" when they don't see the point of what you're saying. They don't understand why you care so deeply, and either want you to explain why you feel they way you do, or to simply end the conversation by pointing out how little is effected by caring about a thing as much as you do.
It can be impossible to tell which they mean, so ask them to clarify. Ask them if they really want to know why you feel how you feel, or if they just want to end the conversation and talk about something else.
If it's the first one, see if you can't think about why you feel how you feel, and articulate that to them. If it's the second, think of something else to talk about.