When it comes to immigration, we may disagree on tactics, but we agree on a lot in principle.

Congrats! You just expressed an opinion. Our President has Opinions as well. So, do I and 63 million Americans and Statistics and they don't agree with yours.

You guys had 2 years of unified GOP government from Jan. '17-Jan. '19 (White House & both houses of Congress) to "build that wall," and... you didn't.

Really, my position is only different from yours in how many billions of dollars I want to spend on border enforcement

Oh, I didn't realize you were a billionaire lol Hey, you ever heard of Tarrifs? I wonder how much we will save taking all the illegals off of the dole? Money freed up to perhaps cover the expense? As far as having the time to build the wall..it was fought tooth an nail at every juncture. Even donated funds for the wall were tangled up in court. The wall will be built! And, it will be paid for by all the money that was being squandered by the Democrats for illegals!

Illegal immigrants are more likely to pay taxes than receive benefits, out of fear of revealing themselves to authorities. To wit:

"IRS estimates that about 6 million unauthorized immigrants file individual income tax returns each year.[9] Research reviewed by the nonpartisan Congressional Budget Office indicates that between 50 percent and 75 percent of unauthorized immigrants pay federal, state, and local taxes.[9] Illegal immigrants are estimated to pay in about $7 billion per year into Social Security.[21] In addition, they spend millions of dollars per year, which supports the US economy and helps to create new jobs. The Texas State Comptroller reported in 2006 that the 1.4 million unauthorized immigrants in Texas added almost $18 billion to the gross state product, and contributed $1.6 billion in state revenue, while costing the state about $1.2 billion in services used.[22]"

Source: https://en.wikipedia.org/wiki/Economic_impact_of_illegal_immigrants_in_the_United_States

The "donated funds" you are talking about do not amount to even a tiny fraction of the amount that it would cost to build even a portion of "the wall." The money raised through that GoFundMe was returned to the donors because it only raised $20 million, far short of the proposed $1 billion goal. https://www.cnbc.com/2019/01/11/gofundme-that-raised-20-million-for-border-wall-will-return-funds.html

How do "unauthorized immigrants" file tax returns? With stolen SSNs that belong to an American that paid those taxes. The "unauthorized immigrants" then steal the refund due to the American that owns that SSN.
The only taxes the illegal alien is paying is sales tax.

So if you don't want to separate families, why not just send them back? Otherwise, they're gaming us and we're letting them, which makes us the idiots.

Obama didn’t do that though. Deportations, yes. Family separations and cages, no. If you want to cite a source be my guest.