We detached this subthread from https://news.ycombinator.com/item?id=18115139 and marked it off-topic.

They are a non-profit that lives on donations to pay it's employees basically. Not your typical for profit venture.

they pretty clearly state they mine every bit of data they can from users phones and from notifications you send when you integrate with their free forever service

Do you have any evidence to backup that claim? Their TOS indicates otherwise[0]: "Signal does not sell, rent or monetize your personal data or content in any way – ever."

[0]: https://signal.org/legal/