I think I would let my kid wear a pharoah costume on Halloween, but not-so-much if he wanted to dress like Hitler ... I'd let him get away with the first if it were clear that it was a costume for an upside-down, anything-goes Carnivale like Halloween -- like Jews dressing as Hamen for Purim -- and couldn't be misunderstood as an adoption of Egypt-ism (or whatever that word should be).

A pharoah costume is "acceptable" because it's distant ... There are people today who adopt Nazi symbols because they want to revive Nazism, and people alive today who were personally affected by Nazism and could be significantly offended. Also, I suppose you could say that slavery is qualitatively different than genocide... and that not all pharoahs were bad guys -- the problem only arose when "there arose in Egypt a pharoah who knew not Joseph ... " (Ex. 1:5?)

If the display were more permanent than a costume, or outside of a Carnivale festival, it raises another wrinkle besides the "identifying with the oppressor" concern you've voiced ... and maybe this is what you're feeling sensitive about --

A hieroglyph is a symbol of a culture and religion that is -- by any definition -- idolatrous: humans were revered as gods, as were forces of nature, and multiple gods were worshiped. Those things are repugnant to Judaism by anyone's definition -- even an atheist's. And hieroglyphics were the "operating system" (or maybe "source code") of those beliefs.

Wearing a pendent with the word, Lieben isn't an inherent adoption of Nazism, and there's plenty of Jewish literature, secular and religious, written in German. Wearing a pendent with an Ankh necessarily connotes embracing values that stand in direct opposition to Judaism. It's not a neutral symbol just because it's old -- it would be like wearing a cross.

And don't get me started on the idea of an Ankh tattoo .......