There are countries in Europe that have had Gulags in the last 50 years, I doubt they are boggled by the idea of a for-profit prison system.
As a European who has lived in America and now in SEA, this "as a European" is used by people who generally don't understand the variety of different life experience of people in Europe.
I think it also tries to convey how different "a very large number of countries and millions of people" views X. It will always be a generalization.
So, if you consider "as a European" to be "Western Europe", it very often applies, overall. It is a generalization, after all. And, as far as generalizations go, I honestly think "as a European", or... maybe better "as a Western European", if you will, to be very useful way to express a very complex connection, and difference in opinion or... zeitgeist. For example, it helps illuminate the dichotomy in the reaction to private philanthropy in the US that should have never been necessary. For Americans, it is accepted that it is a heart warming act, while (for a European), it more often comes across as dystopian.
As a final note, I'm wondering if you might not want to see that argument I'm presenting. Because you point out how my case with ads and money in politics isn't that uncommon in western Europe. Let's be clear, I'm not saying it doesn't happen, or that Europe is problem free or perfect, or anything like that, but the problem and perception of it, is worlds apart. Attack ads come across as a joke that have no place in political discourse, yet, it is everywhere in the US.
But then again, maybe you are right. It is after all pretending to include the "shared voice" of people who do might very well not share that voice. It can be disingenuous. I wonder if making it more specific will still open up for smaller subsets that disagree. If you say "as a Norwegian", you are still implying agreement from others that will very much disagree.
The EU does stuff, but it is far more interested in a being a trade block than a protector of liberal democracy.
There are certain aspects in how things work in the US that are so far disconnected to how it is, in most of Europe, that is baffling. By an large, this difference applies to most of Europe.
It is of course an oversimplification. But, here are a few boggling things: Politics (in particular, money in politics that looks like plain bribery, or political and misleading ads everywhere), for profit private prisons, no maternity leave, unpaid internships, healthcare related personal bankruptcies.
The list goes on and on, and, since this is a by and large difference to Europe, you tend to see the "As a European" phrase.