I understand signing a training contract if the training provides you a type rating that you can immediately use elsewhere. No company can sustain being a training factory. Yes, they COULD be a better place to work and thus MAYBE not need one, but still, I get it.
That said, I have reluctantly signed one pro-rated contract when I was in a job bind. It's was a good company, but the a/c did not require a type.... kinda made me mad.
To each their own if they wish to sign one.