Compassion is being taught in all the 3 vehicles of Buddhism.
It is said clearly in the Lamrim text that all the 3 schools are inter linked and are necessary progressions of one to the other.
Understanding that one must realize the unsatisfactory state of samsara and the importance of developing the spontaneous wish to renounce is the emphasis of the Theravardan school , self liberation seem like the main practice of this school. However, before one can have this wish for self liberation, one must first develop compassion for oneself. Therefore compassion is definitely an important part of the Theravardan school. In their daily practice, Theravardan monks have engaged in numerous community activities eg. hospitals, orphanages , schools etc to care for others
Unfortunately, the emphasis on personal self liberation does mislead the public into thinking compassion teaching is lacking in the Theravardan school which is not true.
Benny, you are right to point this out. I hope this misunderstanding is dispelled as in essence there is really no huge difference between the different schools of Buddhism. Compassion and wisdom are always the 2 main focuses of all the 3 schools.