> Multiple humanitarian organizations define mass displacement as genocide and/or ethnic cleansing.
You're mixing two things here to your advantage. Genocide is (or can be) ethnic cleansing but ethnic cleansing is not genocide. So your "and/or" does some work for you there and makes you correct. However, you said genocide not "genocide and/or ethnic cleansing". You've moved the goalposts.
It'd be odd to redefine any word that ends in '-cide' from actual killing.
> The holocaust literally started with mass deportations/detentions.
Which was ethnic cleansing.
> Then the nazis figured out that it was easier to kill detainees.
You're mixing two things here to your advantage. Genocide is (or can be) ethnic cleansing but ethnic cleansing is not genocide. So your "and/or" does some work for you there and makes you correct. However, you said genocide not "genocide and/or ethnic cleansing". You've moved the goalposts.
It'd be odd to redefine any word that ends in '-cide' from actual killing.
> The holocaust literally started with mass deportations/detentions.
Which was ethnic cleansing.
> Then the nazis figured out that it was easier to kill detainees.
Which was the point which it became a genocide.