A Gallup poll at the end of April found that 27% of Americans view immigration as the most important issue facing the country, topping the economy and inflation.
Piss off your own base to appeal to less than a third of the electorate that isn't going to vote for you anyway.
Also, the "liberal" media has been hell-bent on scaring people on the border. Truth is, a lot of moderates are concerned about the border. And they determine elections. As president, he is expected to address people's concerns.
It's not like the Dem base will switch their votes to Trump.
At this point, now that the nominees are decided, the political game is to attract the swing vote, which is mostly "tough on crime," anti-imigration, and anti-taxation (as it applies to them directly).
Even though none of these policies are actually good for those in the middle.
I find his base to be largely split on this issue. There’s the bleeding hearts who cry for amnesty (Sky Daddy bless their souls) and the at best ambivalent and at worst lipstick racist others.