There are a ton of citizens who would benefit from college but can't afford to go. I struggle to see the utility in discriminating against your own poverty-stricken countrymen in this. What's the real motivation?
Perhaps people are susceptible to recency and trendiness; and perhaps Jeff Bezos also sees opportunistic political timing; and perhaps Jeff Bezos thinks that the uncertain future of hundreds of thousands is a bit tragic; or perhaps the nature of help is naturally uneven, because we are best equipped to help the few issues in front of us.
But your discussion narrowly starts with the character of specifically one Jeff Bezos.
In the view of DACA recipients as unfairly disadvantaged Americans, Jeff Bezos is indeed helping his own countrymen.