Strictly speaking, tenured professors are not an untouchable lot, even though they certainly appear to be. As a method of ensuring this freedom, tenure implies that only those members of the university community that have attained a given level of accomplishment or prestige deserve to have their rights so vehemently protected. This argument fails if we consider that academic freedom is a fundamental principle of the university as an institution, and it should be equally accessible to all. Policy 33 on Ethical Behaviour is also designed to protect academic freedom. Presumably this policy is meant to defend all untenured members of the community.
Stability is certainly an agreeable concept.
However, in light of the current fiscal climate it would be difficult to argue that professors deserve that which nobody else can claim. Moreover, the level of job security provided by tenure makes it signiciantly more difficult to scale down the number of faculty in times of financial distress. Although the apparatus exists, the process is very lengthy and arduous. While tenure offers its holders job security, it does a poor job of meeting its objective of guaranteeing academic freedom. More often than not, money provides a stronger censor than any of the traditional obstructions.