Where does it say they fired the two original bilingual dispatchers?
It looks to me like the district needed 2 more dispatchers, but already had the bilingual part covered by the first two. So they didn't need bilingual ones, and hired accordingly. Then the union *****ed because "bilingual dispatcher" is a union job, but "dispatcher" is not - the district bypassed the existing contract to hire two new non-union dispatchers. When called on it, someone (unknown whether it was the district or the union) wouldn't let the "dispatcher" position join the existing union... so the district canned them. Sounds like both sides are guilty of being idiots.
My department's union deals with this tit-for-tat crap constantly.