Perhaps they feel the IOC won't remove them
Ignoring internal politics from sport federations and only taking into account the number of nations which compete regularly weightlifting is quite widespread. Not athletics/basketball/football widespread, but well above many less inclusive sports so they think the IOC is bluffing. The IOC being relatively lenient over the years probably makes them more confident.
Even in the worst case scenario where the IOC does kick them out and they finally clean house the sport will be welcomed back by the next Olympics so there is little long term concern for the current management to push the edge.
If this was modern pentathlon behaving this way, they would have been kicked out long ago and possibly never return.