I don't mean this in a cynical way. If you consider the time a learning AI spends with humans equivalent to the time a child spends with his family, peers, and teachers while growing up it makes sense. Most children wouldn't fare well if raised by poisonous "nurturers"
That's just the thing, children aren't usually just dumped out into the public to fend for themselves until their parents have slowly conditioned them and exposed them a little at a time. Tay needed some of its contacts to have a higher learning priority assigned than just strangers. And these contacts should have guided Tay through the crap by messaging Tay when she was crossing boundaries or dealing with nasty people. It would likely require a real team of people to support given the volume Tay had to deal with and some automated tools.
Everything that didn't fall in that bucket was clearly just regurgitated quotes from things it had been sent, which clearly needed moderation. But, that's no different than moderating a message board or comment section.