It's not that it's illegal and unconstitutional. It's not that it spends half a trillion or so at a time of 40-year highs in inflation without a direct funding mechanism. It's not even exactly that it's a nakedly cynical ploy to reward a group that votes Democrat right before an election and punish those who don't.
It's that it rewards elites at the expensive of common people. Those who are, by the numbers, much more likely to be either currently successful or if they recently went to college have high future earnings... that are being given a handout by taking from those whom they call when they need plumbing work or their air conditioning fixed or when they want to add an addition to their house.
Maybe it shouldn't matter which group is being robbed to give to which other group. Wrong is wrong regardless of class, race, religion, sexual orientation, or whatever else. But regressive wealth transfers do matter more and offend people's sense of justice in a particular way. When you take from a group that's disproportionately composed of minorities and people in lower income categories and give it to corporate subsidies or student loan payments at a time when average people who don't have the benefit of college degrees are increasingly taking out loans to buy fucking groceries (which, let's face it, printing half a trillion makes even more expensive), they're gonna be more pissed off than if you're just expanding or creating programs aimed at benefiting the poor that happen to be too generous and counterproductive to sustainable social mobility or whatever.
This is this decade's wall street bailout.
It's not just bad policy, it's kicking the most vulnerable when they're already down, handing their wallet to those who are already looking down their noses at them and telling them they're morally wrong if they protest their treatment. Pretending this is fair or moral in any way is a form of gaslighting that the entire Biden administration is engaging in as they ask you to thank them for pissing on you while they dead-ass say it's raining.
Right or wrong, this is how people who aren't elites, who are suffering inflation and recession-like conditions the hardest are feeling, and they have every reason to.