Apparently you can't refrain from picking at Sundt's piece, rather than addressing its substance, so let me dissect your own post.

_Ad hominem_ arguments attempt to reject a prior argument based on of some _irrelevant_ fact about the argument's author.

_"Sundt assumes 'they [Wolling and Duncan] nor most proponents of the plan have made any effort to learn and understand [the situation]' (argument from motives)"_

Sundt's claim is unrefuted and is not _ad hominem. It addresses the _credibility_ of Wolling and Duncan, which is highly relevant and would be permissible in a court of law.

_“and 'proponents are convinced they have the moral high ground' (we have a higher moral ground because we don’t claim the moral high ground)"_

You deceptively fail to include the whole sentence, which Sundt began: "But I admit great “fear” that conventional and uncritical thinking will prevail, because ..." This was not an _argument_, but rather an explanation of the author's feelings.

(continued)