They did not lie. Before D2R launch, Blizzard said that a pre-condition of ladder was the game/server needed to be stable.
Did Blizzard know pre-release how long it would take to fix the game/server issues? If the answer is no, then I would say that they lacked foresight but that is not a lie.
They have released multiple hotfixes. Do you remember them adding game creation queues?
I would not call Blizzard a liar if you are claiming that Blizzard has not introduced fixes to the game/server. If Blizzard did know that it would take many months pre-release, then Blizzard did lie. From what I have read, the former is most likely.
The 2.4 patch notes include multiple additional fixes. You can see these fixes are even stated to specifically fix stability issues.
Graphics
- Fixed artifacting that could occur on certain VFX when using DLSS
- Fixed an issue where the player would become invisible if using Fade behind a transparent wall
- Fixed an issue where ethereal items were appearing invisible when standing behind transparent walls
- Fixed an issue where grass in Tamoe Highland could pop in and out while traversing.
- Fixed an issue where VFX could become missing after playing for an extended period of time on consoles
- Fixed an issue where VFX could appear as black boxes on PS4 in high memory usage scenarios
- Fixed a DLSS-related ghosting artifact that could occur on moving objects while the game camera is stationary
Localization
- Fixed some localization issues with skill tooltips
- Fixed some localization issues related to user presence in the Xbox social menus
- Fixed some localization issues in the Settings menu
- Fixed miscellaneous issues related to localization of chat commands
Online
- Fixed an issue where users in Europe or Korea were unable to block or report users
- Fixed an issue where the right click context menu options in the Friends List would not consistently function
- Fixed an issue where you could not highlight game names and join if using a controller in the Lobby menu.
- Fixed an issue where you could get stuck in an ‘attempting to join’ state if you tried to join a game through the friends list while you were rate limited
- Fixed an issue where swapping between Keyboard and Controller on the front end could rarely force you into the Offline character tab and prevent access to the online tab for a small amount of time.
- Fixed an issue on consoles where online friends who have their presence set to appear ‘Offline’ in their platform settings would appear in the friends list sorted into other online friends rather than with their other offline friends
- Fixed an issue on Switch where if you remove someone from your friends list, they may not correctly get removed
- Fixed a visual issue that could occur when opening the Horadric Cube while in the middle of a trade with another player
- Auto-generated game name and password from game sessions generated using the main menu ‘Play’ button will now be hidden.
- Fixed an issue where your character selection wouldn’t persist if you exited the lobby
Performance
- Fixed an issue where users with 3050 series GPUs would have incorrect default graphics settings
- Fixed a crash that could occur when exiting the game
- Fixed a crash that could occur during the Pandemonium event
- Miscellaneous crash/stability fixes