Why on earth do you think anyone is trying to "prove" the null hypothesis? Neither were they trying to "refute" the original paper, this is simply an exact replication seeking the same effect as Bem reported. It was sufficiently powered to do so under the standard criteria.

So you didn't read the paper then? They conducted a power analysis, determining that each replication required n=41 to have the standard 80% power to detect the effect reported by Bem. This replication wasn't underpowered.