This scene really needs clarification. It led many people believe that King Thranduil, powerful Sindarin Elf, do not approve his son's feelings toward Tauriel because she's a "lowly Silvan Elf". That simply isn't true. Sindarin Elves never looked down to Silvan Elves, though more powerful and skillful, mentally and physically. Even later in the movie, when Tauriel refuses to obey King's order, Legolas tells her: "For 600 years my father has protected you, favored you...you betrayed his trust! Come with me and he will forgive you." So, why would Thranduil protect and favor Tauriel if he doesn't respect her and other Silvan Elves? It's silly. If there are reasons why the King doesn't want Legolas to be with Tauriel, they are probably political. Perhaps he has plans to marry his son to someone important from Lorien or Rivendell and reinforce his connection with other Elven lands in Middle Earth? However, he didn't feel the need to explain himself and his intentions to Tauriel. It's a speculation, of course, but much more comprehensive than "I am a Sinda and I am better than you" speculation.
Whoever read Tolkien's books knows how Sindar stayed WILLINGLY in Middle Earth even though they were invited to Valinor. They wanted to go back to simple life in nature and they merged with Silvan Elves, even adopting their language and names. On the other hand, Silvan Elves, sensing they can learn a lot from Sindar and improve greatly, accepted them willingly to be their leaders. Such was the nature of their mutual respect.
