The Budget Council is not a stakeholder in the CS curriculum. The Budget Council does not have the knowledge or expertise to say anything relevant about the matter - and Dijkstra should know that. That's why it's inappropriate.
I mean, look, if you had a letter signed by the majority of the department, complaining about the chair's decision, then the Budget Council might consider reversing the chair, on the authority of the expertise of the majority of the department. But overrule the chair on the basis of disagreement by one professor? No way. You can't run a university that way, because there's always at least one professor who disagrees with a decision.
An academic knows well that grants and other forms of financing are their lifeblood. It’s also how the government chooses its priorities within academia.
Admittedly, I don’t know anything about who was on the budget committee to which Dijkstra wrote this letter. But it is just ordinary for academics to write proposals outlining their priorities in hopes that the grant/budget/financing committee will bite.
I mean, look, if you had a letter signed by the majority of the department, complaining about the chair's decision, then the Budget Council might consider reversing the chair, on the authority of the expertise of the majority of the department. But overrule the chair on the basis of disagreement by one professor? No way. You can't run a university that way, because there's always at least one professor who disagrees with a decision.