Посещать кладбища на Пасху стали только в советское время, когда храмы были закрыты. Люди, испытывающие потребность собраться, разделить радость, не могли пойти в храмы, которые были закрыты, и шли на кладбище на Пасху вместо того, чтобы пойти через неделю. Кладбище как бы заменило посещение храма. А сейчас, когда храмы открыты, поэтому эта традиция советского времени не может быть оправдана, нужно восстановить церковную традицию: быть в храме в день Пасхи и встретить радостный праздник, а на Радоницу отправиться на кладбище.
From this site.*
Visiting the cemeteries on Easter only started in soviet times, when the churches were closed. People, who felt the need to gather and share the joy, couldn't go to the churches, which were closed, so they went to the cemeteries on Easter instead of waiting another week. The cemetery kind of took the place of the church. And now, when the churches are open, that tradition from soviet times cannot be justified, and church tradition needs to be restored: be at church on Easter Day and celebrate the joyful holiday, and then on Radonitsa go to the cemetery.
So that gets me part way to my explanation; it seems that in a lot of ways, communist times didn't leave as deep of a scar here as they did in Russia. (I'm not saying that there's no mark! Just not as deep.) But why do they go on the Sunday after Easter here? Does anyone know? The same article that I mentioned above says that Radonitsa is the next Tuesday after Easter week.
In Russia we got used to the fact that all transportation goes to the cemeteries on Easter morning. In Moscow they reroute the buses; in Kovrov you couldn't get a taxi or marshrutka for anything. We were a little surprised at how easy it was for Will to get a taxi to church last week. But then this week there weren't any! And as I walked, I did see that all the cars were full of the garish funeral flowers. People have been carrying those around this weekend more than the Easter baskets last week. Even our church was sparsely attended this morning, and we don't follow this tradition!
Ah, another thought just popped into my head: maybe it's Sunday because they'll be at work tomorrow and Tuesday?
Sorry for the stream of consciousness entry here. . . .
*It's nice to see that the article does denounce leaving food offerings and getting drunk at cemetery visits!