It's very easy to say 'so they should be' in knee-jerk reaction but it's not as clear-cut as that, and whether it would achieve anything useful is debatable.
The compulsion probably does not exist because wilful non-appearance is very rare and seems a new phenomenon. The previous murderer to refuse to attend the sentencing hearing was Thomas Cashman, who killed a young girl by firing through the front door of a house in which his quarry - another drug-dealer - had tried to hide.
If nothing else the Courts could install a video link to the holding cells in the building.
