I’m referring to the value of not persecuting based on ethnic or cultural background.

Not everyone in the world holds this value, and relocating to different land is not what makes a person hold one value or another.

So if groups who don’t hold this value grow numerically to the point where the lack of this value becomes dominant, we are putting our own group at risk of being subjected to it in the future, which seems rather unwise.

If you have a civilization, you have a vision about life, and what's good and what's bad, and you want to see it to continue.

That some of them will inevitable change over time is not the same as you preactively having no preference and guidance for your offspring whatsoever, and thinking "no problem, anything goes".

Rich being more numerous than poor is impossible and I don’t think your argument makes any sense there. Being rich is basically being able to direct the labor of lots of poorer people. If everyone is rich nobody is rich.