What was the OG of the starter? I do mine by weight and not sure if you are saying 1 and 3/4 cup or 3/4 cup. Regardless, you want a starter OG of about 1.020-1.030 (.040 at the highest) though, still, a high gravity starter won't kill your yeast.
This is probably just coincidental bad luck, both pitches were dead for some reason before they got pitched. Perhaps the froze? were old? Handled improperly in some way? I have had a few starter fail over the years. Not many but it does sometimes happen.