True. So the most appropriate solution would be for JSO to perform a LIMITED disruptive protest. This would - and we know because it did - hit the papers and everyone would know about it, spreading the message, and aside from those directly affected would gain them a lot of support.
But then you stop. You've done what you needed to. The message is out there, people are talking and thinking about it. And writing to their MPs to express support. And changing the nation's direction via legitimate democratic process.
This is where JSO went so badly wrong. They didn't/wouldn't stop. They kept on disrupting the lives of those around them. They kept ignoring complaints from the public and warnings from the police. They went on to chuck paint at artwork, snooker tables and Stonehenge*. By becoming a bunch of complete and utter wankmuppets they have destroyed any public support they might have had and are now little more than environmental terrorists.
*Yeah I know the details, decomposable powder blah blah. The point is: NOBODY CARES. The only response they get now is "oh no not fucking JSO again".
Sorry I'm not well enough versed in American politics to know who's blue or red.
Whether you should vote or not doesn't depend on the people around you. It is your right to have your say. The result is the cumulative effect of everyone in your area doing the same. Whether you think you're surrounded by millions of blues or millions of reds doesn't make any difference. Your perception may be incorrect, and your analysis, that there is literally zero chance that your vote will matter, is incorrect.
Nobody knows the results of an election until the votes are in and have been counted. It doesn't matter that your area has always been red, blue, green, turquoise, pink or whatever. Areas can change allegiance, and it is by individuals getting out and voting.
If you don't vote, you strengthen the position of those who vote the other way. It is not considered a protest vote because the system would prefer to consider this as voter apathy. If you want to register a protest vote and "none of the above" isn't an option, find the official way to spoil your ballot paper and do that, but whatever you do, get out and vote.