Not to be snarky, but...so? There are laws on the books. We have people who say that they don't agree with them but they are afraid to make a change because votes. And that is true for each party. On one hand the Democrats would probably like a much more liberally open policy on the border than the public at large. It is easier for them to just kind of ignore the law when they run the executive and let in as many as they can. It is the whole "Democrats are not for open borders" that people on the left bring up. They are however in favor of the most lax border and immigration enforcement as is possible for them to get away with.
On the other hand, the GOP are whores for Corporate America, who loves them some cheap labor. Problem is, the people who vote for the GOP want a stricter control of the border and more say so on who comes in. So they aren't really interested in wading into that pool. They just kind of let things go and then use the border as red meat.
All that being said, they do already have enforceable laws on the books. All one need do to start getting the border under control is to enforce the rules as they exist. Trump was attempting to do that and was having success. Bush, Obama, and Biden were/are not as interested. And the people trying to get here know what our unofficial policy on the border is and they react accordingly. Officially, we got laws. Unofficially, get here while you can and get grandfathered in for that next amnesty. That's Joe's handler's policy.