Why Safari? Because it's Apple!
Neither Chrome or Firefox support the HTML5 WebGL flavour of Safari.
Nor did either of these browsers support the HTML5 flavour when the last release of Tourweaver was offered and still don't.
Any release too date has been about iDevice support. Safari working on a PC/Mac was just a side effect to this.
When there is a HTML5 "standard" which is still a long way off. All browsers will be supported.
At the moment stick with Flash for proper computer display.