Is informing your advisor about a community cause considered unprofessional? Background: I'm a PhD stident in Russia with an advisor coming from the US.

There are several community causes that are related or slightly related to academia; two that come to mind are Academics against the immigration executive order and Battle for the the net neutrality. Whenever I learn of a similar community cause, I'm inclined to send a personal email to my advisor, because


I feel it is important to know about these causes,
My advisor can take action and support them.


However, there are concerns that discourage me:


Academics are busy
My advisor might already be aware of the cause, in which case, I'm wasting his time
Emails that seek to support a cause may seem unprofessional, if not downright spam.


Is there a community consensus on how appropriate such messages are?
I don’t think that there is a norm for this kind of interaction, and I think that’s a good thing. Some people will be interested in talking about it with you, others will not. It wildly depends on who your advisor is and what they care about.

It sounds like the issues you’re talking about are issues that are in vogue in the US, a country you aren’t from and potentially have never visited. I would leverage that as a way to talk about it with your professor. Ask the professor about it casually. Say that you have been reading a newspaper or blog or something, that you heard about this political issue in America, and that you were interested in getting his perspective on it. Presumably you don’t know a lot of Americans, and it’s natural to ask one who you already have an established relationship with about it.

Bringing it up in casual conversation is a lot better than email, in my mind. There’s less of a chance for the message to get lost, and I know plenty of academics for whom that’s a major factor.