I have to go to bed soon, but I'll give you my perspective about the gist of your core concern about taxes and loss of stock market returns.

I have a pretty good paying 6-figure job, and am a regular subscriber of /r/financialindependence. I have a pretty decent amount (relative to my expenses) of stock index funds that I intend on using to retire early. So you can say that I'm concerned about taxes, stock returns, and the like. Certainly not the only thing I care about (I certainly care about justice, sustainability, etc.), but I do care about it.

But I think Sanders is honestly the best choice if you care about your long-term stock returns. Because he is far and away the best on 3 main issues that affect stock returns:

*The environment -- Not only may you be dead if the environment goes to shit, but your investments will not likely make much money.

*Inequality -- Inequality is likely to hurt demand, and as the Nobel prize winner Shiller notes in Irrational Exuberance, inequality is likely partly responsible for the huge big up in asset prices since the millennium. This is also likely to hurt your returns.

*War -- If we have another war, that's not going to be great for the economy and the deficit, and will legitimately encourage further terrorist attempts which will probably cause subsequent drops in consumer confidence and stock valuations.

So I don't know what would happen exactly on the financial transaction tax you are talking about on point #2. I bet that anything that would actually pass would be very small, and is unlikely to affect you as a long-term investor. As a long-term investor, you should care more about the stability of the economic and environmental system itself, and Sanders is really the only person who I think is moving us in the right direction on this front.