The thing is, Lilyflower, some of us don't think our "causes" are "left wing". I can't see that in the examples given and my own certainly aren't. Mine are largely humanitarian and about the way we live in the world.
Also, re virtue signalling, it's hard to virtue signal if you mostly just get on with it and do it quietly behind the scenes.
I expect the majority of us on here who have given an example of something (in line with the OP) do/don't do or buy/don't buy in accordance with principles and never crow about it.
In my mind, principles are about the way We live. About more than just buying and travel. They are about others.
I have less energy these days for protests (and so-on) though I have actually been to a coue of demos and protests in the last few years but I no longer put hours into making posters and lobbying for my causes. It does feel like a "cop out" that I'm less "active" and I do sometimes mourn the campaigning, challenging, socially vibrant person I was.
However, it is comparatively easy to send an email to a director of a company, choose to eat differently, support people who are trying to make the world better/ live in line with your ideas. Information is more available now. We don't have to go to the library or write letters to find out the simplest of things. We have Google and Google Scholar at our fingertips. I try to influence by my interactions and conversations. I still write, and yes, I do still boycott Nestle