When did this come into play? I have a manual transmission in my 93 GA and nowhere in the owners manual did it say that towing wasn't recommended. Strange that every tow vehicle that I ever drove (used to drive commercially) was a manual. I never drove a large truck that had an automatic transmission. In fact every car I have owned has had a manual transmission as well.
Even the Ford Granada I used to own years ago had a 200 lb hitchweight, 2000 lb trailer capacity limit, and it was classed as an economy car.