I wouldn't have cussed if you had offered an argument like this earlier on instead of advancing obvious fallacies.

To take up some of your points:

"It is entirely understandable, however, why Congress would want only the discretion-protecting provision of §1252(g) applied even to pending cases: because that provision is specifically directed at the deconstruction, fragmentation, and hence prolongation of removal proceedings."

I'd argue in passing that the fragmentation and prolongation discussed there are to safeguard the (highly abbreviated) rights of an immigrant facing removal by providing an avenue of appeal where few other procedural options exist, as opposed to an expedition of removal proceedings.

I find the logic of using discretion that Congress has given the Executive branch in legislation as a way to speed the deportation process now being used to stop a large section of deporations to be counter to what the legislation intended.

It's hard to agree with your claim that discretion exists purely to speed the deportation process when the statute includes many provisions explicitly granting the Attorney-General discretion to do the opposite, eg 8 USC 1229b which lays out a wide variety of reasons that the Attorney-General might opt to cancel ongoing removal proceedings.

In general, relying on claims about legislative intent is the sign of a weak case; just as ambiguity in contracts is traditionally construed against the drafter, courts tend to hold Congress to the letter rather than the spirit of the law, since reasonable people can disagree about the latter. Congress had no difficulty specifying certain classes of aliens ineligible for relief under subsection C of the section above (spies, terrorist, and war criminals being the most obvious undesirables), so we could equally argue that had Congress intended a more exclusionary standard than that implemented by the executive, it could have legislated one, yet it chose not to do so. Indeed the few modifications to IIRIRA since 1994 have mostly broadened rather than narrowed the options for relief notwithstanding the more rigorous proscriptions against terrorism in the post-9/11 environment. During those 20 years (the majority of which featured GOP control of Congress and some of which featured that and GOP control of the White House) the illegal immigrant population swelled significantly but Congress declined to impose stricter rules or appropriate significant extra resources for enforcement, despite the huge reorganization of the government's domestic security apparatus into the DHS. For example Congress has chosen not to appropriate funds to clear the immigration court backlog, or to modernize the visa overstay database system, or to mandate the use of e-verify by employers (to name but three common complaints from champions of more rigorous enforcement).

This is the heart of the argument against this delay which is an abdication of its responsibilites. I have seen no argument, including from the memo stating the above line that makes me think this is anything but an abdication because the President couldn't get legislation from the lawfully elected body that is responsible for legislation that is to be faithfully executed by the President.

But as I've pointed out (and you have not disputed), The Executive branch is well within its rights to grant blanket stays of removal in response to things like natural disaster or war in foreign countries, and nobody outside of an ideological fringe complains that these are an abdication of responsibility. You might as easily argue that Obama's warning that anyone with a felony conviction will be deported amounts to a abridgement of the due process that Congress provided for - having a felony conviction already makes deportation more likely, but avenues for appeal do exist. It's easy to think of situations where rigid application of this felony-deportation standard will result in miscarriages of justice, as would the 5-year minimum residency requirement. It seems to me that you want the exercise of administrative discretion to tilt only one way, even if promulgating a new set of enforcement priorities (such as not expending resources tracking down people without any criminal record) should result in a more efficient outcome in the aggregate, where by 'efficient' I mean deporting more people who had the highest probability of being subject to removal under the pre-existing criteria due to their criminality.