I think that your comment, while true in spirit, misrepresents some of the mechanics in play here.
> We could revoke the 13th and 14th Amendments and have slavery again--there is no legal impediment to that.
Of course there is - the constitutional amendment process is designed precisely to be an impediment. Unlike a legal proceeding, where courts can create case law essentially at a whim by legal means alone, the constitutional amendment process is a complex and different political process, requiring quite a few procedural stars to align.
One of the problems is that the courts (and, for that matter, Congress and the POTUS) tend not to abide by the text of the constitution, preferring to usurp the political process with their own legal, legislative, or bureaucratic one, respectively.
> We could abolish the EPA, or the IRS, or the NSA. We don't because these have enough supporters who value what they do, today.
I don't think this is true, but I concede that it's not really measurable. What I mean is: the reason that these methods of control persist is not that they have made a convincing case to the public that their mission is laudable and faithfully executed (environmental protection, accurate and fair taxation, and security for US persons vis a vis international dealings). In fact, it's quite plain to see that all three of these agencies have, from time to time, failed spectacularly at these missions, with some incidents attributable to incompetence and others to misconduct.
Instead, I want to suggest that the reason they persist is that they provide convenient mechanisms for exacting power and that they are controlled by people who desire that capacity.
> The 2nd Amendment remains strong today because millions of Americans work every day to keep it that way.
While I agree with this statement, I think that it is somewhat contrary to your previous one. Here you are talking about the preservation of protections offered by the text of a document, which I agree can only be protected by political vigilance. This is fundamentally different from (and perhaps the opposite of) the assertion by entrenched agencies that they operate by political will.
> So, the long-term solution for strong encryption must be a cultural one. We have to be prepared to fight the crypto wars forever, like unions are still fighting the labor wars a century later. Like civil rights activists are fighting racism even today--and will be for the foreseeable future.
Here's where I start to agree with you. This is beautifully put.