I love most genres of music... and sometimes what I listen to gets me a lot of flack. I just think that people who can't appreciate different genres have a very limited intelligence. People with limited intelligence are very often the most vocal about their opinions... just consider the source.
In my opinion, you are free to like whichever music you want. Everyone has their own different taste and liking to things. If 40's-60's music is what makes you happy, continue listening to it and let no one judge you or make you feel odd about it.