Who are these people who are opposed to a Sikh maiden marrying a white?

This is really quite remarkable that it has happened in UK:

http://timesofindia.indiatimes.com/nri/other-news/Inter-faith-wedding-disrupted-at-UK-gurdwara/articleshow/48453754.cms?

Logically, native liberal humanitarian UK white Brits will not oppose such union.

Therefore, these people who oppose this union are purist male Sikhs who want their: 
     1.    womenfolk pure and all for themselves
     2.    virtuous chaste virginal Sikhs all for themselves.

They are opposed to western liberal humanitarian ideas of SHARING.

Can you blame them?