I think the remembrance service and the fact that the families were lied to by the authorities are intrinsically linked though. I do see where you are coming from but Hillsborough affected many families and they were united in their shared grief, and indeed by the city, the football clubs of the city and football supporters in general. Their fans were branded as scum, there were lies about them 'pissing on their own dead' and robbing the victims bodies, spread via a certain 'news'paper, their fans were blamed for jibbing in when that wasn't the cause of what happened and they've had to endure endless slander and lies for the best part of thirty years because the government and South Yorkshire police didn't have the decency to admit to their errors of judgement that caused the deaths of so many.
It isn't so much that they made these errors as, sadly, accidents do happen and people do die in tragic circumstances all the time - it's more the fact that these families were blatantly lied to and branded scum and the attempts to keep the truth from the grieving families meant that they have been unable to properly grieve for their friends and family members who never came home after going to watch an FA Cup semi final in a ground totally unfit for the event,
It almost happened to Spurs fans in their 1981 semi final against Wolves so why wasn't the obvious problems addressed in the intervening 8 years and, as they were not, why was Hillsborough chosen as the venue?
https://www.bbc.co.uk/news/uk-england-merseyside-27614689
As I say, I do understand what you're saying and I'm not having a go, just trying to give my personal opinion as to why the people of the city feel so strongly about it. I used to get annoyed about it myself and I do think there's a lot of reasons outside of Hillsborough for the 'Self Pity City' tag but I've come to realise that saying things like that genuinely does make people think you are referring to Hillsborough so, personally, I'd rather ignore it when they do it than upset people who have been through so much