How many people did he see when he was working, trying to sell his newspapers? You were just one of the many people who chose not to buy a paper. His ignoring you is not personal.
Business and Church are two separate places.
There have been many times when a person told me that I failed to acknowledge him/her while I was walking or riding my bicycle. I was focused on what ever I was doing at the time, or where I was going and never saw the good friend of mine.
As a reader, there have been times when I have been so focused in prayer that I have needed to be nudged to go to the altar to read the Prayers of Petition.
One complaint that people have about the Catholic Church is that people are unfriendly. Is that really true? Why are we at Church if not to give worship to God? In some parishes, individuals are reserved and it takes time to develop lifetime relationships. The person go to Mass, and then immediately home to other obligations.
I currently belong to a small parish that serves donuts after Mass. There is the opportunity in this gregarious parish to know each other, and friendships develop quickly.
The same was true in my last large overseas parish with its large Filipino community.
As others have already stated, it is a different place and setting. It just may take time to become acquainted if that is what you want.