In the text they mention an FDR correction. In which case you typically don’t use 0.05 as the threshold. Bonferroni isn’t the only way to do that correction, but it a valid method (depending on the pvalue distribution). But with only 6 tests, it’s not really that critical. I usually only think of multiple testing correction in the context of thousands of tests.

Given your comment I was expecting something like 5 patients per group. But they had 50 cases and 50 controls. In this context, an uncorrected pvalue of 0.02 is pretty solid.