Yes, Al Shabab has demands to stop the killings in Kenya, because they want the country to be Islamist extremist. That is not to say that Al Shabab's demands are reasonable, but they have them. To that end, they are okay with inflicting terror on innocent women and children in order to oppress them into their way of life.
Al Shabab stated that they wanted the Kenyan forces to leave Somalia or the first bombing would only be the beginning. Al Shabab primarily wants to push these forces out of the country of Somalia and they have been linked with numerous other terrorist-like organizations. The group has been responsible for several deaths.
Terrorists will set guidelines and demands, these should not be pandered to. Although negotiations are positive, if we are to accept and follow the demands of terrorist groups this will send a message of weakness to them and other groups. Sometimes attacking back is necessary in order to protect the masses.
The Al Shabab militant group's demands are not justified. They are a radial group who is using force to obtain their needs and desires. They are not using diplomatic means of government or communication to express their needs. Thus, their demands should not be met. They have not allowed for the other side to express concerns, contributions, or how they can contribute. Therefore, I believe their demands should not be met.