It contains paragraphs that prohibit discrimination. It guarantees asylum for people that are prosecuted in their home country for political views [1]. There's also a paragraph that widens the definition of "German citizen" in the GG to those that were german citizens in 1937 or who lost their german citizenship due to the nazis. After the reunion some groups from russia emigrated to Germany (Russlanddeutsche) [2]. That is wildly different from wanting more immigration.
[1] there's a long laundry list of exceptions to that rule, for example you have to travel straight to germany without passing through a safe country. It's effectively void. See Art 16a https://www.gesetze-im-internet.de/gg/art_16a.html
[2] Article 116 https://www.gesetze-im-internet.de/gg/art_116.html
https://www.merkur.de/politik/asylrecht-oettinger-will-grund...
But here is the counter argument. Europe (if you don’t take the Slavs and the albenians into account) has a negative birth rate. There is no way to sustain current standard of living without immigration. The politicians in Bundestag who control the EU knows that. And if there is one thing that they are afraid of is to encounter the shortage of labour and have to increase wages that comes from that. As the crisis from Covid has shown us.
I think the root cause of the decline of the national and cultural identity of Europe is not because of immigration but because of a local population that has mostly no interest in family formation.
I am in Canada so do not know what the trends are in Europe but I can clearly see that having kids here is quickly becoming a financial burden many people can not afford. Part of it because people want higher living standard while the other is our fucking politicians creating such conditions.
And yes, while Germany and other European countries have great benefits for child rearing, regardless of that a lot of Germans are actually struggling being able to afford living in the cities. Everyone here, myself included probably makes a lot more than an average worker in Germany.