Americans don't even protest on weekdays, they wait for a weekend to do it. So it is easy to say that they aren't serious but on the other hand, they're a lot closer to the knife's edge of stability and missing a day of work can get them fired (especially in at-will employment states), Europe is not like this as much.
That's somewhat understandable, what I find more interesting is that people around me won't show up unless it's between 70-80 degrees out.
And if they lose the job they lose their insurance, thus their medication.
This increases stakes to protest quite a lot, compared to European worker protection and social security.