[inertiatic]

It certainly reads like an attack, and that's to someone who agrees with the sentiment. And as an observation, in professional contexts you can generally be poetic and figurative when talking about good things ("Gary is such a godsent and a genius for showing us the way to restructure our department"), but it's in bad taste to do it to express negative things ("I worked with Gary and he's an absolute mouth-breather and defecated all over our infrastructure").