Fat-shaming seems likely to inflict harm, which in my opinion makes it appear obviously HP'esque.
Folks do a lot of unhealthy things for a lot of reasons. They are also not in total control over what they do and how it affects their bodies at the individual level. If one wants others to make better decisions they should instead choose to inspire them with care and tact while promoting environs conducive to positive changes and developments.
Shaming is also not in keeping with egalitarian, solidaristic, or even individualistic values. I am concerned it implies fat people are inferior, perceived as having interests in conflict with those of others deemed to be of healthy weights, and are becoming subjected to excessive pressures to use their rights and freedoms in accordance to what the community prefers. This matter reveals subtle differences in shades of authoritarianism among self-described adherents to liberal values or ideologies - authoritarianism in how they interact with people.
I would not go so far as to describe shamers as HP though. An individual act of vice does not a vicious person make. Please apply your good intentions in a wiser and less destructive way.