Because he got caught and now has to pretend to care. He declared no deportations for any Haitians who reach America, because they vote Democrat, he also declared no Cubans are welcome and all would be deported despite Federal law saying they automatically get asylum, Biden doesn't want Cubans because they hate Communism and vote Republican. Biden illegally tried to prevent reporters from being allowed to cover his border disaster but after the cat was out of the bag he has had to do damage control.
Now Biden is lying and claims he has sealed the border when nothing could be further from the truth. They go back and forth at will between the US and Mexico.