CuteEditor, like nearly all other Rich Text Box controls, does not work at all with Safari and mostly works with Gecko browsers like Firefox but with some issues.

You are wrong to say "they all do the same thing" - they do not. With Safari you just see a regular text box, but with Firefox you see the toolbars and the formatting works quite well.

This is not caused by CuteEditor, but by the lack of necessary functionality in the browsers. The only true cross-browser editors are based on Flash or Java.