Sometimes I wonder why Twitter doesn't just ban his account like they would any other troll on the internet.
I'm not sure if you mean this seriously, or in an exasperated but joking manner. If you are serious, it's because Trump has done more for the legitimacy and usage of Twitter than any engineer, businessperson, or celebrity other than Dorsey & cofounders. To be clear: Twitter may take a tough official stance against Trump, but behind closed doors he is the MVP.
1. Barack Obama, 118 million.
2. Justin Bieber, 111.
3. Katy Perry, 108.
4. Rihanna, 96.
5. Taylor Swift, 86.
6. Christiano Ronoldy, 84.
7. Lady Gaga, 81.
8. Donald Trump, 80.
9. Ellen DeGeneres, 80.
10. Ariana Grande, 74.
The next highest politican is Indian Prime Minister Modi, at #17 with 57 million. The Office of the Prime Minister of India is at #42, with 35 million. Obama, Trump, and Modi are the only politicians in the top 50.
The only individuals in the top 50 who are not those three or entertainers (counting athletes as entertainers) are Bill Gates at #22 with 50 million and Elon Musk at 47 with 34 million.
[1] https://en.wikipedia.org/wiki/List_of_most-followed_Twitter_...