> 1) Kids are unlikely to be as effective. 2) There's not that many kids.

Neither of those even support the argument that a change from equal minimum wage would have the effect of moving jobs from adults to kids.

The first would be a good argument for a smaller displacement effect from allowing teens to work with equal minimum wage to adults conpared to not allowing them to work at all than would occur at equal effectiveness, the second semana yo be a sortear of an argument about the magnitude of effect but without a definition of what “that many” meand in context is only a sketch.

> It's all just motivated reasoning to argue against a significant minimum wage.

it's not an argument against ‘a significant minimim wage’ at all.