I just did a bit of a Google search about Bill Gates and depopulation, but I couldn't find a reputable news source on the first couple of pages of hits, just a lot of conspiracy theory nutjob sites, so I added 'youtube' into my search terms to see if I could find what their analysis is based on. On youtube most of the clips of Bill Gates's speeches are posted up and annotated by right-wing conspiracy nutjobs and rednecks talking about the Illuminati, planned genocide and how man-made climate change is a myth. There's an awful lot about how medicine is bad for you, especially vaccination, and that Bill Gates is just fronting a big, covert extermination machine.
It is well known that Bill Gates likes to spend his money on vaccinating children and adults against communicable and potentially fatal illnesses. His vision for a reduction in the world's population includes everyone living longer and healthier and having fewer children, through the combined interventions of vaccination, contraceptive technology and improved healthcare. This somehow gets translated by his critics into "vaccines that are actually a form of lethal injection."
I seriously doubt it is worth anybody's time and energy getting worked up into a frenzy about how Bill Gates is trying to kill us all so there's more of the world free for him to enjoy by himself.