"I don't agree, if multiculturalism unites then why do people come in to britain but want their own shops places of worship etc? I don't think that is what they want, I think they want the best of both worlds, to leave their own country and turns ours into a mini version of theirs but only with the bits that suit, what happened to when in Rome?"
Have you ever been to Rome, OP? Do you know much about Roman history? An interesting parallel.
The Romans went around the world raping and pillaging, much like we did with the Empire.
Rome itself is a hugely multicultural city. Even when the Romans decided to all of a sudden change their religion to Christianity, Judaism still existed. Today in Rome there are Synagogues, Temples, Mosques and a plethora of languages spoken.
You don't come across as having thought this through to be honest. "why are we one of the only countries that do this?" strikes me as a positively stupid thing to say. Have you travelled? Visited any other countries? Because you clearly have no idea. Bring Australia up as a prime example - their indigenous population are in a distinct minority and have been treated appallingly by generations of (mostly British) immigrants. What makes you give this as an example?
I love the thought that some incredibly dimwitted people have of 'sending them all back to their own country'. Imagine. Half of Australia, America, a lot of Africa, not to mention the rest of the world would have to come and live in the UK. The Brits love to procreate and spread their genes all over the world. Think about it.