See The Manner of Procedure in Administrative Recourse and in the Removal or Transfer of Parish Priests, as this seems to be a case of transfer. (I am not a canon lawyer.)
I too am not a canon lawyer and I won't debate canon law here. However, there is nothing in your link that contradicts my statement or indicates that this bishop did not act legitimately. What the link does outline are the detailed rules of appeal for the religious involved. This process does not include self appointed "righteously indignant" parishioners.
My complaint with the original poster is in their apparent disregard for the authority and role of bishops within the Church. No good Catholic should work to undermine the authority of their bishop. It is not the role of lay people to appeal or protest a bishop's decisions about priest assignments, and undermining this foundation hurts the entire church. The original poster seems unable to be able to comprehend that the ends of trying to defend a "good priest" do not justify means which are destructive to the structure of the church. This "the ends justify the means" attitude is immoral and decidedly un-Catholic. Being on the conservative side doesn't make you better than the liberals, behaving with conservative ideals does. Regardless of the original poster's political persuasion, organizing a protest within the Church is an immoral liberal tactic. It doesn't matter how conservative they may be, their first loyalty should be with the parish, not the priest. The original poster needs to take a better look in the mirror and see the harm caused by their actions.