If only they would have simply written "gamma ray" instead of γ-ray, but I suppose there are the bandwidth savings to consider...
I think it's a valid criticism, not sure why the downvote rain happened. Too snarky, maybe?
Unless you really mean that they did this for the purpose of saving a few bytes, then I disagree with you.
They are mostly unproductive, and express an opinion more akin to noise than anything else.
Don't try to predict when downvotes will occur. Only predict that aligning your comment perfectly with the general sentiment of HN's echochamber and the capricious views of some of its moderators, will likely result in a general trend of upvotes.
If you ardently pine for someone else's approval, conform to their every whim.