I'm surprised they haven't banned that phrase already like they did with "learn to code".

If the phrase is used to harass people in a targeted manner, then sure. Running a platform that excludes those who harass people is quite reasonable, and necessary if you want to keep those sweet advertising numbers up.

"Learn to code" was a critique of how journalists covered job losses in blue-collar industries, compared to how they covered job losses in journalism. Harassment has become a seriously devalued concept if people replying to a tweet unfavorably qualifies. When public figures make tweets, they aren't entitled to unanimous agreement and applause.