I get it, and I think it is fine to feel bad for Williams regarding his knee, lack of QB coaching, lack of good play calling, etc., but only to the extent that the starting QB decision was based on performance from last year. As far as we know, and from what the coaches have stated publicly, the decision was made entirely on their performances in camp. If the public statements are true (and I have no reason to believe otherwise), both QBs had an equal shake at things, and the coaches felt like one QB gave the team a better opportunity to win.
Due to the OC coaching change, you can make the case that this was perhaps a more objective and fair process than it might usually be. Particularly because Taylor did not recruit any of the QBs. Taylor came in with no clear biases, installed his offense, evaluated the QBs, and made a decision on who he thought ran it best. He chose Huntley. It appears all QBs had equal opportunity to demonstrate their prowess in practice and scrimmages. So while it is never fun to be demoted, and we can feel bad for Troy in that regard, the opportunity and determination seems to have been fair (whether the determination was correct, is yet to be seen and will almost certainly be second-guessed by everybody at every incompletion or interception thrown by Huntley).
In fact, the selection of Huntley indicates even moreso that the decision was made objectively on the merits because selecting Troy would seem to be the default (i.e., most everybody expected it and he was the starter last year). Sticking with Troy would have been safe, and very few people would have second-guessed Taylor. To buck that inertia requires moxie and would usually only be done if the decision is very clearly correct on the merits.