That's a hard pass for me. I'd imagine the person who makes the decision about hiring you won't even know if you've opted out because the data is gathered at the corporate level. But that's just my guess.
Like so many others, you've mixed up general society with law enforcement. We defend the right for the Nazis to say their piece without being imprisoned. Running a business profiting from letting Nazis publish their speech is a choice, and not a necessary one. Using and supporting the social relevance of a social network that voluntarily publishes hate speech for profit is a choice, and not a necessary one.
It's more about keeping the downloads code independent from the cache code. Once one depends on the other, you can't change either one without considering the other. Minimizing dependencies is a way of reducing complexity.
That's right, I was referring to the browser/client developer. The browser cache is treated as ephemeral storage so it's not a safe assumption that a previously downloaded file is still there.
It's simpler code to re-download the file than retrieve what cached version may or may not exist in memory or on disk. Developers often like to keep code simple at the expense of some kinds of efficiency, like this.
An image is usually small enough to be downloaded in no time on a fast connection, which is what developers usually have and don't stop to think that others might not have.
A video is probably being streamed so earlier segments may no longer be present locally.