The author's post came off the same way you've described (to my ears), while targeting design without any concrete examples so it's all conjecture as far as I'm concerned. Designers and developers should work closely together, I depend on them for their technical feasibility/performance subject matter expertise.
"Reddit redesign [...] it’s still slow, unnecessary, and buggy."
I agree Reddit's redesign is a mess and it's largely the implementation and development by the hands of developers whose job it is to code and otherwise discuss performance tradeoffs with product team/design stakeholders for exactly all the items you describe.
How are designers to blame for how it was coded? Devs should have voiced concern if they knew the proposed designs would be a performance disaster on the publicly facing front-end.
"Reddit redesign [...] it’s still slow, unnecessary, and buggy."
I agree Reddit's redesign is a mess and it's largely the implementation and development by the hands of developers whose job it is to code and otherwise discuss performance tradeoffs with product team/design stakeholders for exactly all the items you describe.
How are designers to blame for how it was coded? Devs should have voiced concern if they knew the proposed designs would be a performance disaster on the publicly facing front-end.