The reasons are two fold as I shall explain:

1) There is a globalist interest in breaking down any nationalist sentiment in individual countries. In order to achieve this they introduce draconian hatespeech legislation while simultaeneously flooding target countries with people who have no nationalist sentiment whatsoever.

Because of the hatespeech laws, which are really just censorship laws, people with a nationalist sentiment cannot mount a political response.

This results in nationalists becoming demoralised and giving up on the idea of nationality, thus making it easier to create supranational structures that govern unilaterally.

2) There is a more short term goal of 'manufacturing consent' for international biometric digital identification systems.

Create a massive immigration problem, ratchet up public demand for a viable solution to the mess, present your already drafted draconian policies and people may be desperate enough go go along with it.