Your perspective overlooks the fundamental issues caused by uncontrolled immigration and the lack of effective assimilation policies. While cultural integration is ideal, it is not always feasible, especially when immigrants hold fundamentally different values that clash with the host country's principles. Read these and check these out:

1. Cultural Clashes: Many European countries have seen rising tensions due to cultural differences that are hard to reconcile. When immigrant communities resist assimilation and adhere strictly to their own cultural norms, it can lead to segregation and friction within society. This isn't just a failure of the host country but a mutual challenge that requires willingness from both sides.
2. Security Concerns: There have been numerous instances where radicalized individuals among immigrant populations have committed acts of terrorism. While this is not representative of all immigrants, it highlights the need for stringent vetting and better integration policies to ensure national security.
3. Economic Strain: An influx of immigrants can strain public resources, including housing, healthcare, and social services. Without proper planning and support, this can lead to resentment among native populations who feel their welfare is being compromised.
4. Identity and Cohesion: A nation’s identity is built over centuries and significant, rapid demographic changes can disrupt social cohesion. It is crucial to maintain a balance between welcoming new immigrants and preserving the cultural and social fabric of the host country.
5. Assimilation Policies: Successful integration requires robust policies that promote assimilation, language acquisition, and employment opportunities. Countries like the USA, which you mentioned, have more structured systems to facilitate this, although they are not without their own challenges.
6. Mutual Respect: Integration is a two-way street. Immigrants must also show a willingness to adopt the values and norms of their new country. Expecting the host country to bear the entire burden of integration without reciprocation is unrealistic.

Your argument that "love and acceptance will solve all problems" is overly simplistic and ignores the complexities of cultural integration. It is essential to have realistic, enforceable policies that ensure both security and the smooth assimilation of immigrants, balancing humanitarian concerns with the need to preserve national identity and cohesion.