Criticizing tone is one of the least productive ways to engage with an idea. It doesn't address the idea itself, and perception of tone is very subjective, so it stimulates an exchange of opinions, which is not what we want to read in the HN comments.

Refer to DH2 in "How to Disagree" by Paul Graham (2008) http://www.paulgraham.com/disagree.html (not that this is a disagreement... but the article is still relevant)