I agree that the inability to plan is the injustice (but of course that is tied to the lack of the communication).
If women had had the same opportunities as men from the start, the idea of 'equalising' pension ages would be fairer - but we didn't. Apart from the fact that many women were encouraged to stay at home when they had children, we did not (on the whole) have the same opportunities as boys. The older 50s cohort will have started work when unequal pay was allowed, and the younger ones (like me) will have seen boys with the same qualifications given jobs that led directly to management when girls went into 'dead end' roles. Yes, some women had the same opportunities as boys, or fought their way up in a man's world (there are always posts pointing this out, and of course I congratulate those women for their presence of mind and determination), but they were fairly thin on the ground.
In the work I retired from (university lecturer) I was paid the same as men on my grade, which seems fair, but the university had a 20% gender pay gap (still does, AFAIK), as do many other workplaces, because men climb the ladder faster, largely because of having no time off for children or spells of part-time working for family reasons. All of that feeds into pension provision, both in final salary schemes and in years worked (and contributions paid) in annuity-based pensions.
When I started work it was legal to deny part-time staff, and those on temporary contracts (in both cases predominantly women) access to occupational pension schemes, too. This meant that I didn't start paying into one until I was 37, which again, impacted on my pension.
People who say things like 'you wanted equality, now you've got it' are either missing the point or being spiteful, IMO. It was never equal, but at least the earlier retirement age went some way to compensating for that.