tranduil shuts everyone out in order to save the few of his alliance left
I believe that following the destruction of Beleriand and the War of Wrath, Oropher (and the rest of the Sindar Elves unwilling to leave Middle-earth) traveled to Greenwood the Great and merged with the Silvan Elves. It’s part of my headcanon that in order to merge these Elves, Oropher wed his son to a Silvan Elf. Not سے طرف کی an arranged marriage. Just as an act of good faith. And I like to think that when the Sindar Elves renounced their way of life to embrace the Silvan Elves’ rustic way of living, they embraced the way they celebrated most, their festivities.