They would much rather confidently repeat a date that is totally unfounded rubbish which will have to be rolled back later, because then they can blame the engineering team for not delivering to their estimate.
Personally I consider it more important to constantly narrow down any uncertainties over time, than having an initial estimate that holds. The closer it gets to any deadline, the less uncertainty I want (need) to have because the less options remain to react to changes.
And frankly, this usually not only applies to estimates but also to things that these estimates rely upon. The longer the timeline, the more room for circumstances and requirements to change.