The guy who made the original tweet claimed he was a busy man who couldn't be expected to check every little fact, and he seemed genuinely surprised his tweet went viral. Um, okay. Tweet in haste, repent at leisure.
Still, the people who made the tweet viral aren't exactly blameless. In this day of so-called "citizen journalism", you're responsible for what you share.
It's popular in some quarters to deride the mainstream media as untrustworthy and biased. In the strictest sense it's true that big-name news outlets make mistakes and have implicit (or explicit) biases. However, it's also true that they have policies in place to keep them from intentional errors, and for the most part the people who work at these outlets don't do it for the money: they do it because they believe in reporting the truth.
The guy who tweets out a random observation may believe he's reporting the truth, too. But does he really care whether he's doing so? The guy who tweeted about the buses didn't care.
If you don't trust the mainstream media, whom do you trust to tell you what's going on in the world? Anyone, whether you know his motives or not? Only those who say things with which you agree?
In that case, you might as well be talking to yourself. And in fact, if you take your distrust far enough, that's exactly where you'll wind up.