I think AM is as much to blame as Honda. Imagine if instead of the Honda engine it was a Merc engine. You would never blame it on Merc, you'd blame it on AM (unless Merc was having the same issues). We don't actually know whose fault it is. Maybe Honda made an engine that vibrates too much, maybe AM made a chassis that can't handle the engine.
IMO it's a bad look on Newey because AM is on this together with Honda. Not sharing the blame just strains the relationship.