I usually think it in vain to post a comment on something that I fundamentally disagree with, because I rarely find an author with a strong point of view who has not already found a choir to preach to, so that speaking up would be futile—I would be drowned out, or villanized.
The only kinds of comments which seem to me to be worth making are those in which: You agree, and offer some novel corroboration; You agree with the conclusion, but disagree with the means; Or you raise a question, without treating of the conclusion at all.
The obvious possibility would be to reproduce the entire hierarchy, but to a different purpose.
DH0: "Stop agreeing with me, you're making me look bad." DH1: "You should let someone else make that argument." DH2: "That (arrogant,presumptuous,juvenile) tone won't go over well." DH3: "You're going to offend people who believe X." DH4: "I heard an argument Y against this," or "How do you solve problem Y"? DH5: "Have you considered solution Z' to problem Z?" DH6: "You're formulating your own belief incorrectly."
But I don't think that your bounds hold here. DH0 is still maximally unhelpful, but DH6 may be just as bad. DH1 may be the wisest advice that you can receive. DH3 is less helpful than DH2 (better to be asked to express your beliefs more politely, than to be asked to conceal them). And DH4 is more polite than DH5 (better to solicit the author's opinion on a difficulty, than to obtrude your own).