Grace, I have very mixed feelings regarding this subject.
On the one hand, we have seen the negative results of mass immigration in Europe, The cultural differences in the treatment of women is one thing that sticks out in my mind. The love of Sharia Law that clashes badly with our own laws is another problem.
What we don't ever see are the stories of those immigrants who are now living a peaceful life without constant threat of violence or death. For some to the younger people this is the first time in their lives they have enjoyed this luxury.
We hear talk of immigrants refusal to assimilate into our culture and society. This is not limited to the USA and Europe.
I have friends and family who now live in Costa Rica. Many Americans and Europeans live in that country but choose to live in gated communities surrounded by other Americans and Europeans. Many refuse to learn the local language and almost demand that the maids and gardeners they hire speak English. My point is that the failure of immigrants to assimilate is a world wide issue.
There are those however who move to Costa Rica or Panama, buy a house or rent an apartment in the areas populated by the locals. They are the one's who seem to get the most out of the experience of living in a different country. They learn to speak Spanish, meet their neighbors, and are welcome guests at many of the local celebrations. They accept the cultural differences and try their best to blend in, and don't complain about those things they can't change.
Those immigrants who don't like the American or European way of life and culture should leave and go to back where they came from. Their claims of being offended by so many things is wearing very thin.
My rule is if you don't like it where you are, just go somewhere else to find happiness.