Being honest sometimes results in being a jerk. No big deal, an emotionally mature adult can handle it.
Being honest never requires being a jerk. That is always a choice you make.
Remove context from his statement and surrogate anything we have objective knowledge of (e.g. housing market 2009) and the statement morphs from "arrogant prediction and condescension" to an appropriate comment on reality.
There are very few contexts I can think of where "telling a fat person they are fat" is useful information for that person.
"Being honest" isn't a valid defense against being an asshat.