First off, I'm not going to speak on behalf of the elected leadership of the union, but I can tell you my perspective as a negotiator for the union.
The union lobbied for years for military time to be included for vacation accrual. With respect to the years of service issue, it was hugely contentious within the membership. From our perspective, the only way we could resolve this issue was to let them vote on the matter. In fact, it could be argued that they already did vote on the matter because it was contained in the collective agreement that got ratified in 2018, when the definition got changed.