You have that chance, you need to download bitcoin core softward and launch a node. No need to commit to mining, just having a node gives you the opportunity to vote on the type of transactions you're accepting.
You can find the download link to the software at the top of every page on this forum at: News: Latest stable version of Bitcoin Core...
I realize you think it's crap but it's literally how you activate your vote. The money comes second. You don't get a choice to to decide the favored chain if you're not running a node. You just get to decide to go with the flow or go with the "no". It's like the feeling people have voting in a two party system...they feel compelled to vote for one of the two major parties and voting a third party would be like voting for the dying coin version.
I find it a misconception. If there is no Hashrate in the UASF chain, there isn't even a vote to be had. So whichever node you run has little meaning. This is all between the Miners and Exchanges. Miners will propose solutions, Exchanges will delegate the vote to the crowd by listing them.
UASF would be just the same without the 1 person 1 node propaganda. You might argue it has social relevance. Like a sit in in front of the white house. Or a hunger strike. It's a legitimate way to show discontent. But in the end, it is not how you exercise your vote. By running a node, you are just signalling intention. To act upon it you have to put your money or it is meaningless.
Your money is how you vote. Which is a perfect system for me, because it ensures you vote responsibly and look for information rather than being spoonfed by CNN.