Exactly what I've been thinking. The Dems basically won two branches of government and they could push through rapid fire reforms if they put their minds to it. But we all know that's not how politics works.
This holiday was possible because it doesn't take any actual work to make it a reality; they just have to call it a holiday and it magically becomes one. They can appear like they did something, but they don't have to sacrifice breaking deals with the lobbyists who put/keep them in power or dedicate any resources for a project.
Most importantly, it doesn't actually solve any problems. It's not even going to take a year until Juneteenth becomes a 'barbeque holiday' where people just enjoy the day off except for blue checkmarks that go out of their way to remind everyone of the actual meaning behind it. Nobody's life was measurably made better by this, and that's essential for any politician or political party in a binary system to stay in power. Both parties have learned that fear and anxiety are what drives people to the polls, so if either of them actually began to solve the problems supposedly caused by their opposition, there's less motivation for their base to show up on election day. Like if the economy wasn't constantly in shambles or in danger of becoming so, there'd be no reason for a sane person to vote for Republicans. And if we ever had racial equality in this country, why vote for people who tease the idea of setting up a socialist dictatorship?
The lives of black people in this country will be just as bad if not worse off by 2024, but I guarantee the dems are never going to stop telling them "hey remember we gave you that holiday? we've done so much for the black community! but uh oh, we haven't done enough! vote for us and it'll be for realz this time!"
It's funny that you see this as a perceived slight against trump. It's telling in some ways since this is a lame attempt by the democrats to try and lesson the sting of racism.
The day has existed for some time. It was only when trump knowingly tried to hold a rally in a city that had previously been bombed in white supremist terrorist attacks against black Americans, then it gained some notoriety.
This gesture by biden, although nice, does nothing to placate the roots of racism that this nation was built upon.