I dont think you should have a dislike button there will always be differences of opinion on all subjects People come here to share their experiences what they are going through some are emotionally upset due to personal circumstances so they write their answers as a form of comfort
If someone dislikes what they have wrote then they might end up in a worse condition than what they started with And there are those people who will never be happy and will disagree with everyone and everything and will use the dislike button relentlessly
So in my opinion a dislike button is not a good idea