Personal stances on what constitites being overweight vary a lot.
Individual beauty standards are also very subjective.
So there is often a vast of conflicting opinions relating to these types of issues.
It is normal for someone with a chip on their shoulder who obsessively looks for something/somebody to project their own issues onto to generally find many opportunities of doing so.
People who have embraced obviously pro-ana agendas or are committed to 'thinspiration' ambitions, will often view everyone else as fat and gluttonous.
Even with zero personal knowledge of the dietary lifestyles and exercise regimes that those other people have.