Overlord,it's touched briefly in the show, that ainz has felt disconnected from his humanity ever since being isekai'd, and has little empathy towards humans. Honestly, I don't think the explaination or logical consistence even matters, given that I have no issue with the "problem". What matters is the show is a load of fun, and unconventional elements in any show are inherently interesting. ---
Your palace may last forever, but my yurt can go anywhere.