Complex sentence: They eventually declared them undesirable to remain among German citizens and society, which over time dehumanised the Jews; arguably, these actions desensitised Germans to the extent that it resulted in the Holocaust.
Split into simpler sentences: They eventually declared them undesirable to remain among German citizens and society, which over time dehumanised the Jews. Arguably, these actions desensitised Germans to the extent that it resulted in the Holocaust.