To be clear, you are wrong.... I did not say or even infer either was illegal. Fraud is defined by Black's law dictionary as "A knowing misrepresentation of the truth or concealment of a material fact to induce another to act to his or her detriment." IME, in most cases those who manage their income for ACA subsidies are not concealing what they are doing but most who play the Medicaid game are more stealthy.
Also, there is a matter of degree. According to Kaiser, the average ACA credit is $371/month and ranges from $178/month to $592/month. So a wealthy person playing the subsidy game would get a $2,150 to $7,100 annual benefit.
OTOH, the average nursing home cost per Medicaid is $6,600/month and ranges from $4,800/month to $9,900/month. So a wealthy person who receives taxpayer subsidized nursing home care get an annual benefit of $57,600 to $118,800....broadly 20 times the benefit of those playing the ACA game.
Finally, to play the nursing home game one needs to actually do something.... transfer assets to beneficiaries with 5 years foresight.... they are knowingly taking action to conceal their wealth to induce the government to pay for their nursing home costs.
To play the ACA game most people are actually not doing anything.... despite their wealth their income absent any actions on their part would result in a subsidy (I know that is true in my case).... they are just either deferring starting their pension or social security or not withdrawing from retirement accounts to avoid increasing their income. In some cases, they might be increasing their income just enough to avoid Medicaid... just replacing one government paid benefit (Medicaid health insurance) with another (ACA subsidies).
IMO there is a huge difference between taking actions to specifically receive costly Medicaid nursing home benefits and not taking action to benefit from ACA subsidies.
And as a retired CPA I think I have a good understanding of it... and the difference.