I have some soft agreement with your arguments. The flexibility of enforcement is certainly an issue for both parties, but I have to point out that Obama's bullshit is just that, bullshit. Obama wasn't deporting abuela or gang members in the interior, he was turning away the South Americans at the border and recategorizing those as deportations. It's all lies, damn lies and statistics!
And you know EXACTLY why he did so, because the Mexican Majority fucking DESPISES all the other """hispanics"""" and sees them all as niggers from even more failed states, with very few exceptions. Back when the Democrat/Uniparty Establishment actually had non-retards trying to steer their increasingly oversized boat, they recognized that the easiest way to keep the latino vote was to keep as few major ethnic voting blocks as possible, especially after having virtually no gains with Cubans. Then some retards went all in on red to spite Trump or some equally retarded reason and now we have the latinos realizing that they like not having the spic's spics in their cities.
This is why the methodology has always been wiggly wobbly, because it's been a constant threat by the people who actually know and didn't sit on their laurels yet could rarely actually speak up against the suits in charge who were just as alienated from the common people as any other 5th yacht club corporation.