Like most of the general public, I have no desire to associate with criminals. If you build your union on a foundation of illegal acts, there's no reason for anyone to believe you'll stop once it gets fully established. Existing unions in the United States provide ample proof of that.
(Oh, and by the way, the Teamsters, whose site you linked to, figure prominently in quite a number of those news stories. There really isn't a better example I can think of of why "Workers need to be willing to break the law in order to win victories against the people that make the laws..." goes down a bad path than them. The Wikipedia article for them contains the word "corrupt" 31 times.)
That's the cleverest counterargument you could manage?
I choose to interpret that, as most readers will, as conceding to my arguments.
Not if they want to win, they don't. Anarchism won nothing at the turn of the century. Organized (note the adjective!) Labor broke through when it became a political movement with representation in government.
Look, the point here is that if you want to win a unionization fight (which is a legal victory, it will happen in courts and with contracts) you have to fight using legal tools. Pulling anarchist tricks like this just makes you feel better, it does nothing but make management's position stronger.
If we leave rhetoric aside, what she's done is the equivalent of sending a leaflet or putting up a poster on company property. That's not strictly 'proper', but life does not happen in courtrooms. You actually have talk to people, let them know what's happening, organise, etc. Courtroom is where the fight is settled in it's last stages.
I disagree that only rights granted by courts are effective in winning labor struggles. Strikes, legal or not, are required for advancing labor's cause.
This worker was attempting to organize her colleagues in an extremely tame way. There was no property damage. We should show our unadulterated support to embolden the working class.