A general strike is a strike action in which participants cease all economic activity, such as working, to strengthen the bargaining position of a trade union or achieve a common social or political goal. They are organised by large coalitions of political, social, and labour organizations and may also include rallies, marches, boycotts, civil disobedience, non-payment of taxes, and other forms of direct or indirect action. Additionally, general strikes might exclude care workers, such as teachers, doctors, and nurses.
Historically, the term general strike has referred primarily to solidarity action, which is a multi-sector strike that is organised by trade unions who strike together in order to force pressure on employers to begin negotiations or offer more favourable terms to the strikers; though not all strikers may have a material interest in each other's negotiations, they all have a material interest in maintaining and strengthening the collective efficacy of strikes as a bargaining tool.
So, a general strike is illegal in the USA.
But, remember the history of unions. The Luddites were textile workers who were upset that the mill and factory owners were breaking the law and denying their rights. With the government ignoring their rights and the owners trampling over them, the Luddites prepared to fight:
Then they broke things:
And they killed:
And the government killed them:
The point is, trade unions were a compromise. Get rid of trade unions and what you get instead is mob violence against factory owners. People die.
"Meet our demands or we're going to walk around outside holding signs instead of working."
vs.
"Meet our demands or we're kill you and destroy your equipment."
If a general strike is illegal, then why stop at a strike? "In for a penny, in for a pound."
If you read the last part of the explanation general strikes are official strikes of one union to support another, so general strikes are acceptable as long as it's not an official strike and can be organized by a union or group of people.
Sure, there are some technicalities. But, the whole "rule of law" hardly matters in the US these days. Most likely the Trump junta would declare any general strike to be illegal. After all, it involved "antifa", a known terrorist organization.
The general point is that the more that reasonable and measured dissent and protest are not allowed, the more pressure is going to build up, and eventually you're going to get chaotic and violent riots.