Basically I did a two LEFT OUTER JOIN deep inside each other, which ended up working as I intended:

SELECT "table_a".* FROM "table_a"
LEFT OUTER JOIN "table b"
ON "table_b"."table_a_id" = "table_a"."id"
AND "table_b"."active" = true
LEFT OUTER JOIN "table_c"
ON "table_b"."table_c_id" = "table_c"."id" 
AND "table_c"."active" = true
WHERE "table_b"."id" IS NULL OR "table_c"."id" IS NULL