As far as the other laws I bet if careful research were done you would see that the federal government has given the states the authority to set the speed limits for their portion of the interstate highways. I haven't looked into the ICE issue carefully to answer that one.
Without researching it, I'd imagine that the point of the 200 gallon threshold is to establish some rational threshold between 'personal use' and a presumption that the person is engaged in commerce (and needing to be federally regulated).
As far as the interstate highway issue, that's not how we get speed limits - it's kind of the opposite. States have the authority to set speed limits. The Feds get the state's to change their limit by presenting them a choice - "change it to what we'd prefer or lose a % of federal highway dollars." Beck when the Feds were pushing "55 saves lives (and gas)," I think Montana actually told the Feds, "that's okay, keep your $$$, it's not that much anyway."
Ahhhh, federalism - the cooperative relationship that allows state and federal governments to function (though the above example sounds more like extortion than cooperation to me). There are times when the Feds completely own the regulation of a particular thing, other times when the states do, and still others when the two regulators co-exist.
That brings us to the differing allowances between the state and federal governments for the home winemaker... if you buy the "threshold for commerce" argument, and the notion that the Feds aren't really regulating what you do for personal consumption, that's left to the states (all that health, welfare and safety nonsense we hear with some routine). Provided, you can read the laws in a way that you're not violating either, you're good. So if the state prohibits home winemaking altogether, they can (because 0 gallons is less than 200).
Finally, the marijuana thing - the Feds classify it as a schedule 1 substance - no accepted medical use and highly addictive - on their schedule of controlled substances. The only way to change that is to: a) amend the federal law to specifically deschedule pot; or, b) the president and DHS can, by a particular regulatory process, deschedule it. Neither of those things have happened. So, it's still illegal...
The fact that any administration takes the position that they don't like the law and choose to ignore it rather than follow the constitutionally established processes to change it... we'll, that's crap (and this comment has nothing to do with how I feel about marijuana at all). It breeds contempt for the law and creates some bizarre by products (like the fact that the proceeds of marijuana commerce can't go through federally regulated banking institutions - so there are these huge warehouses out there loaded with money inside and heavily armed guards on the outside - crazy).