Wiping out student debt is not a bad idea, since no one has the slightest intention of ever trying to collect £100 billion of debt. In practice, wiping it out would not cost a penny.
But the sore nearly-winner claim that Labour pledged to do so has crashed and burned with the public. Even majorities of Conservative supporters do not believe it.
In any case, are we expected to believe that those particular voters who were "deceived" might otherwise have voted Conservative, or indeed any other way apart from Labour? Pull the other one.