Cloudflare had a nice technic to address the bot problem (if you use their name servers). It'll respect and use the robots.txt while sending the remaining bots to a deep black hole.
That said, one of the biggest websites in the world not respecting it is definitely a noteworthy story. Hopefully another one of the biggest websites in the world (formerly known as Twitter) eventually respects it as well instead of not even disclosing itself via a user agent and pretending to be Safari running on iOS.
You're talking about one (yes, biggest) but millions of other bots don't follow must be a bigger story.
The people trying to use it to block or limit bots are uninformed and/or misinformed.