Depends how you're going about it mate. Everybody has the right to dislike something, it is called racial tolerance because you tolerate it! There are advantages and disadvantages. People who vote for the BNP for example, are not thinking about the boundless advantages that a multicultural society can bring them, e.g. who is going to drive them home when they themselves are too drunk to drive? Who will be the doctor who saves their life? Who will sell them fags and milk down the local corner shop?
You mentioned the disadvantages, which I happen to agree with in many respects. Music is just down to personal taste, but what you mentioned about olde England really struck a chord with me. I am from Coventry, and there is one street in particular here where back in the day, in pictures, you can see post offices, blacksmiths, wool shops, olde ale houses and pubs. The sort of thing I like. Staples of British culture if you will.
On that same street now, you have kebab houses, halal meat shops, polish supermarkets and one pub. This brings me to the major disadvantage of multiculturalism, if the change is too abrupt, people may begin to resent these immigrants who come here, in most part to make an honest living, live by our laws, and respect our place here. But they do bring a large part of their culture here too, in doing so, there is obviously going to be some friction.
What we need is a balance. Not the BNPs vitriolic, violent and amateurist 'get them out' attitude, and certainly not New Labours 'let everyone in to p i s s off middle England' policy, but something has to be done. So to answer your question, is it racist and wrong to dislike multiculturalism? Not really, what can anyone do? Force you to like it?
I will probably get a trillion and a half thumbs down for not immediately and unequivocally declaring racism in all its forms completely wrong (which it is), but think about it, all I am saying is multiculturalism has good points and bad points, and I don't think it is racist to say that this country has so many people in it, soon it may cease to function.