I completely understand this. Not everyone enjoys dining with a large group of people. You rarely go to a four star restaurant and expect to be seated with six other people. There's nothing wrong with people not wanting to be social at dinner. I know the number of tables for two is far less than the demand.
Many people go on a cruise for a romantic time with each other and want that time. My wife and I have taken a couple of these cruises and had a table for two and enjoyed it. Those cruises were our time together and we greatly enjoyed it. After 22 years we haven't ran out of things to talk about.