To a chronically obese person: Just stop eating.
To a person in poverty: Just save up money and find a job.
To a person in poverty: Just save up money and find a job.
The problem, however, is that addressing the root cause is extremely difficult, or even impossible (for those trying to give advice), so people don't know what else to say. For the person in poverty, for instance, the root causes are numerous and systemic in that society, and pretty much impossible for anyone to fix anytime soon. So what else do you do or say?
I don't know, but if one can't think of anything better, then I think it's better to shut up, or just acknowledge the problem and be supportive but refrain from offering unwanted non-solutions that implicitly blame the victim and trivialize their problem (you aren't "just doing X" therefore it's on you) and simultaneously frustrate/anger/depress them because "just do X" is impossible (or not a solution to their problem).