If one style of writing applications is far more prone to having “bad software”, consider that this is a valuable signal about the difficulty of using that style effectively. SPAs require you to take on ownership of more hard to debug challenges and that's an important factor to consider when selecting tools.
The GP was not saying "bad software is bad"; they pointed out a lot of footguns that are introduced by going the SPA route. "More code -> more (opportunities for) bugs" is the truism at play here.
Without SPA you have horrific 10page forms and the challenge of maintaining state as you go back and forth to make edits.
The hard part is managing state, and there is no way to avoid it if your product is not purely readonly. SPA is one strategy, and a pretty good one.