It's good to source all of your information, but we're up against censorious manipulative liars, who will quash all dissent and contrary information. Even archiving websites sometimes doesn't work, as they're removed for wrongthink.

And, when debating someone who is acting in bad faith, they use "source?!" as a cudgel and deflection, forcing you to jump through and endless parade of hoops, and adhering to the most stringent of rules, that they never, ever apply to their own position. Even when the things you're stating are plainly obvious truths and simple logic, they're decry "SOURCE?!", not as a means to truth, but with malicious intent. When debating such a person, you could cite every single claim you make a hundred fold, they would reject all of it, and proudly declare themselves the winner.