My one and a half year old learned the alphabet by watching a cartoon several times. I think there is a healthy balance to be found somewhere between 24/7 and zero.
We have a four year old who we've tried to limit watching TV, because you can see a noticeable difference in demeanor and attitude when the TV is on versus when playing by themselves or with us. Of course there's going to be some TV time, but for a kid under 2, I would tend to agree with the study, with the addition that even something like an iPad can be much more of a learning tool.
If you asked any worker "why does there have to be a lunch break" they'd look at you like you were insane. I think the same applies here.
I really hope you didn't just say that there's no difference in learning between talking with your kid, or having them zone out in front of the tv.
I spend a lot of time reading to my kids and playing with them. I've seen how much they pick up that way. However, I haven't come across a book or way to hold my 2 yr old's attention to get them to learn ABCs and their sounds. She loves to read and see pictures and point at things but she isn't learning letters that way.
She watches about 15-20 mins of Leapfrog: Letter Factory and I was amazed how quickly she started recognizing her letters.
I'm not suggesting TV is a replacement to reading but rather than another medium of learning is a tool that can be leveraged.
Also my point was more towards the article headline (less so the content) in general where a blanket statement like 'watching TV = bad for infants'. Rather we should find a balance between reading, music, outside play and even TV.