I'm guessing that they didn't include the CTS because the only stick under the price limit uses the "old" 220 hp V6. The new 255 hp "high feature" V6 comes only with the automatic.
If you want a V6 sport package car, which is what Cadillac would probably want to supply for a test like this, you have to take the high feature V6 and the automatic.
Keep in mind that automakers supply cars for these tests. If I worked in the PR department for Cadillac and I knew the V6 we were using for the stick shift was on its way out - and wouldn't do well in the comparison - I'd probably not make a car available. Especially with the CTS-V just launched getting pretty favourable reviews all around. Why risk a less-than-stellar review on a car that probably won't be around next year anyway. Best to wait for the launch of the high feature stick (which I believe will be available next year) and get positive reviews then.