The friend of certainty is time. One day perhaps then we won’t even call ourselves Americans. I doubt the 1860s will happen again anytime soon. Maybe something closer in scale to Blair Mountain.
Look to history. We’ve had two. Look at the words explaining the necessity of independence in the declaration of independence. Those were not hollow words but detailed a long series of abuses. Then look to the causes of the Civil War. A perfidious institution anathematic to the very core ideal of the nation, that all men are created equal.
Our times doubtless have our problems but the do not meet nearly the standard set in the past.
Because most haven’t I will actually answer the call of the question. Voting is perhaps the most important way one can voice their opinion. And carries more effect than most words the average man or woman can utter.
The largest argument against these types of stances is that it will create a spoiler effect. This usually operates on the premise that a vote to a candidate is owed and not earned and or that it is impossible to achieve a different outcome besides one of the two establishment candidates. This second premise being the results of people who decry voting 3rd party as useless based on a restriction with no physical or legal basis imposed on our society by our society. There’s nothing stopping people from electing anyone else on the ballot.
If you can acknowledge that we as a society have this power the idea of accepting a lesser evil is weakened. If you vote for a lesser evil you perpetuate the broken system you hate. In your example Gaza, if someone feels that the issue is so important it merits a principled stance how can they not take the stance?
It’s a matter of pragmatism vs principles.