The repressor wants to require people applying for unemployment benefits to take drug tests.

There is no particular need for this, nor any justification. It's simply an opportunity for kicking people when they are down.

The US government imposes on many organizations the requirement to fire people for using marijuana even in states that have legalized it.

Even supposing that people should be fired for being high on marijuana while at work, it would be an injustice to fire them based on a test that shows they used it some time in the past month. Perhaps there is a way to legislate that such tests are not valid tests for use of marijuana.