LocalPro you should follow Higney's advice and educate yourself further on the grievance process and the difference in handling between grievances and discharge cases.
That said, ALPA is not obligated to provide representation in ALL cases. Say, someone who leaves the line for management and then has pass travel fraud exposed. Or a check airman who threatens his first officer with busted checkrides if he talk to management after allowing some offline flight attendant to ride the jumpseat because he's hoping to get some.
Some people are bad and just don't deserve to have this job. In fifteen years, and several at EXA, there are very, very few people who I have not seen ALPA represent. Those who are refused are usually pretty notorious. Or odious.