One of the common tactics in debates-- on both right and left sides -- is to point out some inconsistency on someone's stance with respect to their actual behavior.
This is sometimes absolutely valid -- if someone claims to support one thing but then clearly is doing the opposite, this is certainly an indication that they aren't serious about their initial claim (or possibly they're flat-out lying).
However, in many cases, especially larger political or economic stances, the very facts of existence and the rules and requirements of society and one's business within it puts people in a position where it is extremely difficult, if not impossible, to avoid participating in various activities that may in specific elements contradict your personal stances or preference.
I, for instance, am against exploiting and mistreating workers. This means I have a LOT of dislike for many large corporations, if not all of them, including Amazon, Apple, Microsoft, and so on and so forth. Yet I'm sitting here typing on a machine that was undoubtedly to one degree or another made by underpaid, mistreated workers. My books are on Amazon, and if I want them to have any chance of selling halfway decently they had BETTER be there because that's the biggest single market for books anywhere, making up the vast majority of ebook sales and a huge chunk of physical book sales.
Similarly, someone can be a full-on Taxation is Theft libertarian, but if you have a family and the only support you can get to keep them going is Social Security, then you bloody well take it, because you have a much more direct and personal responsibility to keep your family safe and fed than you do being a purist.
Politicians are in some ways more subject to this than anyone else. You may sincerely, like Bernie and AOC, want to fight against the entrenched elitism in the society, to address global warming and other environmental concerns, and believe firmly in reining in spending on various areas while increasing spending in others that you believe will help the most people. But in order to do that job, you have to talk WITH the elites -- civilly -- and maybe even concede something in one area in order to get something you think is more important. You have to go to meetings with other politicians and such that may be widely separated but close in time -- and so, like everyone else in your business, you will be getting in a jet and flying there when you'd pollute much less if you went by car or train. You will even likely prefer to take a charter rather than a standard commercial jet because you can get a lot more work done, and done privately, on the way.
None of these mean that the beliefs are insincerely held. They mean that even if you want to fight the system, you're still IN the system, and unless you're already at the point where you can step outside of it -- so rich and powerful that you need not accommodate anyone else -- you will have to do what the system requires even while you're trying to change it.
You can use the system to support you while fighting it, and indeed, for almost everyone, you HAVE to.
This is true of, say, celebrities who are trying to promote social or political change. The fact is that their power to change anything is directly dependent on the wealth and exposure OF being a celebrity -- and so the common "gotcha" of "if you were serious you'd have given away all YOUR money" is directly ignoring the fact that in our society, that would mean giving up the strongest lever you have to try to affect change.
In that situation, we're all apparent hypocrites by necessity.
The important thing is to avoid DELIBERATE and OPTIONAL hypocrisy -- when one reasonably can. That's where you see whether people actually believe what they say.