The author comes out as a arrogant. Looks like he expects his team to be skilled but it's crystal-clear that he wouldn't follow a leader that is less skilled than he is.
My take is that if the author cannot explain what BigO is in 5 to 10 minutes and how to use it effectively, providing simple examples and leaving room for questions, he is absolutely NOT fit for the job - I don't think he understand what a team leader actually is.
I had 4 team leaders/CTOs so far, the first was extremely technical (probably the best, I've never came across another DevOps that was so well-rounded technically). The second was less so, but he was extremely well rounded in managing people. I came to appreciate his ability to express a concern or point mistakes I've made without insulting me in any way.
Being a leader is about taking technical decisions but first and foremost it is about teaching and managing ppl.
In any sort of leadership role you're supposed to be trying to extract the best work from your people. Generally you are not going to be able to do that effectively if you are looking down on them. Give them a bit of respect, encourage incentives and comaraderie. Your new job is to be explaining stuff to them so they can work better. If you don't like them figure out how to make them better - its usually easier and way less expensive than firing and hiring.