Because Mozilla doesn't care about the privacy of their users. If they did, Pocket would be easily disabled, and they would have zero telemetry (like Ungoogled Chromium).
I don't think the things you cite necessarily mean "Mozilla doesn't care about the privacy of it's users". There's always room for improvement, but "they're not perfect" != "they don't care".
Tangentially related: ungoogled Chromium has some impact on Google's monetisation, but zero impact on their browser monopoly, because in the end you're still using their browser engine. So if you're talking about counteracting browser monopoly, ungoogled Chromium is not a good choice.
I will name drop Librewolf as the "Ungoogled Chromium" of Firefox-based browsers. However, the web itself is tightly controlled by Google, and for me using UG Chromium is the best bet. I've stopped caring about the browser monopoly and instead looked for ways to minimize my usage of browsers and the web in general.
Tangentially related: ungoogled Chromium has some impact on Google's monetisation, but zero impact on their browser monopoly, because in the end you're still using their browser engine. So if you're talking about counteracting browser monopoly, ungoogled Chromium is not a good choice.