I don't believe children under two years of age should watch a lot of television, educational or not. I'm not supportive of using television, videos or DVDs as 'babysitters'. Extended periods in front of the television in replace of social interaction with parents or other family members cannot be a good thing. The Academy of American Pediatrics advised in 1998 that no child under age two should watch television.
Everything is moderation is my general rule (except when it comes to chocolate unfortunately). I do recall having the need to put a DVD on so that I could empty the dishwasher...my daughter liked to crawl into the dishwasher as I unloaded and loaded it. For me, putting in a Baby Einstein or Signing Time video or DVD on was a sanity and safety issue for the 5 minutes it took me to take care of the dishwasher!
I do believe there is benefit to co-viewing music and baby sign language type of television shows and DVDs. Co-viewing, for short periods, is good for one-to-one snuggling time as well as parents will learn ways to interact with thier children when the television is off, through signing and singing for example.
If a new parent does let their baby or toddler under 2 watch the occassionaly educational preschool television show or baby sign language DVD I don't think it will do horrible harm. I think these parents don't need to be made feel guilty, they need more support and help at home as well as more opportunities to interact and socialize outside the home.