The question asked wasn't whether the Civil Rights protesters shouldn't have inconvenienced people. It's whether a company should force its workers to join a protest.
In this case, the mechanism of political action is constricting the labor supply instead of giving cash to politicians.
It seems crazy for a company to force workers to join a protest, until you think about how they force workers to turn a profit and then donate to politicians that would happily oppress those same workers.
Companies also collectively fire people to bolster their profits, maybe we should demand they do some mass firings for a good cause. Trump supporters, maybe?
(On a related note, there are some regulations around mass layoffs: https://www.doleta.gov/programs/factsht/warn.htm
American companies will run a series of layoffs JUST below the limit to avoid the reporting mandates! Kind of like structuring deposits of $9,999 to avoid the reporting requirement at $10k. Interesting.)