I'v already said before that the open borders attitude of the Dems and Biden appear to be an opposite, stick it in face reaction to Trump's criminal action of separating children from their parents.
Petty shit flinging isn't a one-way street.
However, beyond that component is the fact that the border issue has been relatively ignored by both parties for decades because of the need for cheap labour. America isn't viable if it needs to pay the going rate demanded by Americans.
This is also the reason why US corporations skipped town and headed off to China.
Stop trying to place blame and offer some solution!
The same rules apply as did for Hitler's demonizing of the jews. There was nothing in it to gain other than turning sentiments of the German people against others who were seen as different.