That is an incredibly dismissive and reductive argument to make. "Feeling sad about your job" isn't limited to burnt out software engineers with a safety net. It can also apply to, for example, someone stuck in a shitty, low paying job with few, if any, prospects for better employment. The lack of a path to a decent future can, in itself, be incredibly demoralizing, even if your present circumstances might be decent. After all, what's the point in continuing if I can see that it's all downhill from here?