I couldn't disagree more. That's my favourite thing about these chairs - they're cheap and ugly, but i actually find them really nice to sit in. There's just the right amount of flex to support you and bend to the shape of your body without feeling flimsy. Most cheap chairs are either totally inflexible, or too flimsy.
I always hesitate to sit in them because I always get the impression that they’re dirty. I think that’s a problem with them being white: every speck of dirt stands out.
They also get really hot and bendy if you leave them in the sun. I recall have the legs of one collapse under me in Brazil because of this (I'm not a particular large person!).