With the Feds (and their low low subs) you get exactly what you pay for. ...effectively nothing. The only case I know of when a pilot asked the Feds for assistance, that pilot got none. They were told by the Feds "we agree with the company, tough luck, see you later".
Said pilot subsequently joined ALPA and despite the grievance being pre-existing, received a substantial amount of peer-support, although they were not eligible for ALPA legal assistance.
ALPA have a long history of assisting pilots in "trouble". There are some who may even be in prison now, but for the help of ALPA. That's why I pay my ALPA subs without complaint. I know that if I need help, I will get it.
I doubt members of the Federation can be quite so sure.