James E,
As I am certain you appreciate, in a less heavily moderated (and not so predominantly North American) online community some of your points about Russia's actions (... violently invaded territory of sovereign nations, supported a coup in a European state, massacred civilians in air strikes) would be immediately countered with a "WhatAbout" kind of argument, which, in turn, would most likely be countered by American exceptionalism trump card ("Quod licet Iovi non licet bovi"). In a matter of minutes the tread would turn into a flame war of epic proportions - precisely because our minds are set, and nothing the other side will ever say will make us change our position. Travelling to the opponents' country is very unlikely to bring about change in our - or theirs - world outlook with regard to these issues.
The issue of Crimea, if I may, is much more interesting in this respect - and I think an argument can be made that Travel as a Political Act concept well applies to visiting that part of the world.
By the way, I do not readily accept the Mexico wanting Arizona analogy without the obvious modification (i.e. rephrase the question as "Would it be OK for Arizona to join Mexico if the majority of Arizona residents wanted to join Mexico?). The answer from the vast majority of posters here would still, of course, be an emphatic "NO", and, as you correctly pointed out, it would be largely driven by the mere fact that it is "our back yard".
But Crimea isn't our back yard, just like Kosovo wasn't our back yard. And as such, it offers a unique opportunity to try and objectively put to the test the two conflicting narratives of present-day Crimea - that peddled by Western mass media and the one churned out by Russian state propaganda (for those who would like to indulge - check out rt.com or sputniknews.com).
You can talk to people who voted in what they see as a legitimate referendum to secede from Ukraine, and you can talk to people who refer to Russian rule as occupation. You can talk to oppressed Crimean Tatars and non-oppressed Crimean Tatars; ethnic Russians and ethnic Ukrainians. You can find people in Sevastopol who were against "Russian invasion" but changed their minds when Ukrainian activists disrupted energy supply to the peninsula, resulting in 12 to 20-hour daily blackouts throughout the harsh winter months, and you can find people in Yalta who supported "reunification" but changed their minds when they realized that higher pensions under the new rule are offset by higher prices. You can find people that found it repulsive that in a 2011 interview an ex-president of Ukraine had referred to their region as a "festering carbuncle on the face of Ukraine" and you can meet those who find it repulsive that mainland Russians do not treat them as equals.
Basically, you would be doing the reporters' job, but unlike the vast majority of them who have never set foot in Crimea, you would have a first-hand experience - and ethical and moral grounds to pass judgment (which, incidentally, would carry a lot more weight precisely because it is based on your own witness testimony).
I visited in 2016, armed with a shining set of preconceived notions, political views, and expectations - and most of them were shattered to smithereens.