This is a topic that has been on my mind for a long time and until today I've been too scared to voice my opinions on it for fear of backlash from my ethnic community.
I'm aware this topic has been done to death by european nationals that are experiencing the downsides of living in a society where they are being forced to get used to living with so many different people with societal values that are completely different to theirs in order to seem poilitically correct and tolerant despite the harm it's doing to their own society. But as somewhat of an outsider and as someone that this issue Europe ( The migrant crisis) is facing doesn't directly affect I'd like to share what I think of the issue. And my opinions aren't restricted to just Europe but to the world at large.
Will try to keep it short.
1. Multiculturalism is a catalyst to war and conflict. Lets take this scenario for example; In a chemistry lab, all the different chemicals are stored separately in their own special bottles specifically designed for the chemical that is being stored within. What happens when you decide to pour all those chemicals in one large vat? There's likely going to be an explosion that'd tear the roof off. Different places have different societal values and it's impossible to ask people to just 'respect' that. Some people can and some people can not. For example some cultures accept child marriages and think sex with minors is justifiable but becasue of my own upbringing and personal morals I just can't accept it and I never will. I personally can not even share a room with someone that thinks that that's okay. It's not difficult how to see how that could possibly lead to conflict and tensions between two groups. Which brings me to my next point.
2. Multiculturalism incites racial hatred. People would love to assume that being around people who are completely different to you culturally and scoially would cause people to become more tolerant but it does the exact opposite. It highlights the irreconcilable differences between the two groups of people and constantly being exposed to societal values tnat you don't agree with/hate will one way or another lead to believing that anyone who holds such opinions must be less than human and scum. It breeds an us vs them mentality. It's obvious that this will become problematic in the long run.
3. It affects the legal/judicial system in a country. Once a country's government starts changing it's laws in order to appease a minority rather than the majority then there's a problem. For example, a country in which child marriage is illegal laxing it's laws on child marriage in order to appease a small minority of people. There's no way that won't casue outrage. That's not how legal systems should work.
4. It dilutes the culture of the host nation. As much as people don't want to admit it, having so many different people coming to live in one place who must by all means take every aspect of their own culture with them, effectively erodes the cultural and national identity of the place they're moving to and it's not fair to the natives of that place. I sure as hell wouldn't want thousands of people to come in to my country and refuse to integrate thereby burying my country's rich cultural heritage..
After all that's been said, it's clear that multiculturalism is just a utopian fantasy that can't be fully achieved anywhere as much as it pains me to say. I can't think of one place where people of conflicting backgrounds and origins live together in perfect peace and harmony.
You even get family members and relatives calling you derogatory names for trying to integrate in the new society. (Ie south asians calling other well adjusted south asians 'coconuts'
By no means a solution but some advice:
When deciding to relocate to a new country you must make this decision. Are you going to be able to accept the laws, societal values and culture of the host nation? Are you going to be kind and respectful to locals even if you don't agree with their culture? Will you make an effort to learn the language of the host nation you are moving to? Are you going to try and integrate into the society and not form cliques and seperate communities that refuse to mix with others?
If the answer to all these is no then I think it's best to stay in your own country.
The only thing I can justify taking along with you are aspects of your culture that your host nation can actively benefit from (ie cuisine, entertainment etc)
Tldr: Multiculturalism doesn't work effectively anywhere
Conflicting opinions are welcome