You sure have the clueless part right.
First, how is this law going to be enforced? A robot can be scaled to do any portion of a human's job, or the jobs of multiple people. See that thing that looks like a washing machine with paper slots - that's our engineering department. That thing that looks like a pizza oven is our production line. Government inspectors will be unable to determine how many people a robot replaces, or even if a particular machine is even a robot. If the government decides just to count the change in the number of warm bodies, the company will shut down and form 2 new companies. The first will be just the CEO. The other will be just robots, located in a place that doesn't tax robots and with all maintenance and ancillary functions outsourced.
Second, what's a robot? Machines will be designed to skirt any legal definition of a robot.
Third, the economics changes. Robots will cut costs, and if a manufacturer doesn't cut selling prices to match then competition will pop up to undercut that manufacturer. There won't be new profits to tax.
In his glee at having found a new way to oppress people, Gates hasn't thought through the obvious flaws in his nefarious scheme.