You don't need to give monks secondary skill counterattack for them to counterattack, that's native to the job and always active. You learn those passive skills in order to give counter attack to other jobs that don't have it. There are a few exceptions to this rule though, such as HP + x %. There are also a few passive traits that don't stack on freelancer, for example the same HP boost abilities and a few of the passive abilities of the new jobs in the GBA version.

I like giving barehanded to my white mages :p, and sometimes I make a berserker monk just cause they tear through f-in everything.