Translation:On Shavuot one usually eats dairy products.
I don't know about way back then, but nowadays it's definitely not true. I personally am דתי, and although I do wait six hours after eating meat before I consume milk, I consume dairy products almost every day, as do nearly all of my religious family, friends and community. Where did you hear that from?
By the way, you can read several of the real reasons for eating dairy on Shavuot here.