This is absolutely true. The demo in the original article seems quite deceptive in that respect. Nobody would attempt to resize a window by launching their cursor at the corner with great speed as the demo shows. The resize pointer seems to show in exactly the right place, and allows for an extra hit area slightly outside the rounded corner — I don’t see any problem with that.

As for the fact that one cannot resize from inside the window, it makes absolute sense for every other corner of the window, where the user would instead be clicking an icon or some other button (try the top right corner of the finder, where the search button sits).

So, while I agree on the whole that Tahoe is a huge step backwards in terms of design, this seems like an odd gripe to point out, as it doesn’t in fact seem to be an issue at all.

Edit: clarification