We don’t know the minute when X started throttling links to news, but we know that Elon Musk asked for it, and we basically know why.
Musk disdains the “legacy media.” He wanted people to spend more time in his walled garden, and to build the walls so high that you couldn’t see outside of them. For the umpteenth time, maybe for the last time, people who published news were lulled into giving it away gratis.