Why? People care more about what happens around them. I care more about housing issues in the Bay Area than I do the same problem in New York. I care more about Oakland crime rates than Chicago crime rates. People care more about things that directly impact them and those close to them. If people see their hometowns and communities falling apart when the main industry moves overseas, and only receive second-order benefits like slightly reduced price of good a few years later, what incentive do they have to support globalism?
Don't get me wrong, we are failing many of those communities. But is not a failure to stop globalization, it is a failure to share the gains of globalization more broadly with those most affected by its negatives. We can do both. Is not either let them starve or stop global trade, both can be prevented. Besides, a lot of those industries that keep being brought up as examples of victims of globalization only ever got to be as significant as they were due to globalization: consider the American manufacturing industry, which greatly increased in significance after WW2 mostly due to the demand for its production in war-ravaged Europe. Or the American agricultural industry, where people complain about Mexican workers "stealing" jobs, while ignoring that Mexico consumes $17.7 billion of that agricultural production from U.S. exports.
I agree with you the most here, and think it's true that unless a trade policy of that nature is implemented very carefully it could easily cause more harm than good. On the other hand, I think concerns about a complete walling off of collaboration/trade, or US manufacturers suddenly becoming unaware of international markets are overstated.
Manufacturers who have stayed alive already compete aggressively on price, which for them is more about materials management, relationships with suppliers (NXP, Samtec, Maxim, whoever), and process optimization. Component cost varies pretty dramatically by region, and how effectively a US based shop can navigate that is a big determining factor in how competitive they are with China/Mexico/etc.
From that perspective, most of the burden of something like a border adjustment tax is primarily on their customers, especially if they only do mid or low volume / high complexity runs (think medical/telecom/some consumer stuff). High volume / low complexity isn't something most US shops are geared for these days [1], so manufacturing will likely remain overseas and see a price increase in line with whatever policy change occurs. That probably won't hold true for high volume / high complexity (smartphones, etc) where cost of total assembly is higher. That seems to align with all the chatter about Foxconn, Samsung, Sharp, Toyota, etc. investing in US operations. [2][3]
The risks you mention are absolutely real, and my biggest hope at this stage is that any proposed changes are drafted and discussed openly, and given ample time for public review and comment.
1. http://www.assemblymag.com/articles/83764-managing-high-mix-...
2. https://www.macrumors.com/2017/02/08/sharp-lead-on-7-billion...
3. https://www.nytimes.com/2017/02/12/business/trump-asia-aliba...
If you don't like Facebook or other global institutions, there's no effective way to opt out.
I am not a centralist when it comes to the official international institutions precisely because the no opt-out you describe (which is true for official institutions, not so much for Facebook). But at the same time, without international cooperation and with "every nation for itself" we end up much worse off at a personal and species level.
Not that shadow profiles are a good thing, though. But I think this is drifting from the original topic, Facebook is, as of now, eminently more "escapable" than most nation states are. Certainly than any of the great powers, even if you don't live anywhere close to them.
Globalization-in-current-practice has a lot of specific problems: wealth inequality, environmental and labor laws race to the bottom, etc. But those are things to work on without throwing globalization away (the same way that propaganda on social networks can be tackled without either: "ban social media" or "internet sovereignty: internet propaganda for the national government where you live and no one else"). There are big issues with specific models of globalization. But nationalism flaws are inherent, a nationalist utopia is strictly worse than a globalist utopia, and historically nationalist reality has been worse than globalist reality (e.g. for all its problems, the E.U. beats what came before it).