Circa 1960, I went on a boy scout trip through the southern states from Ontario. In Mississippi, I met a girl about my age and we decided to become pen pals. We exchanged letters regularly throughout our high school years and when she graduated she wrote that she would be attending Ole Miss like her dad did, but it wouldn't be the same since they now allowed... (She then made a disparaging remark about how integration had spoiled the university using language that I won't repeat here.)
I had enjoyed many years of exchanges of letters with this girl, but never wrote her another letter. My mom thought that I should have written her a letter of explanation and she was probably right, but I never did. I often wondered if she figured out why I didn't answer her last letter.
Sometimes it seems that people have a dark side that we don't see till after we have time invested and have built a relationship.