I think there is a semantic difference. To me, "How to explain the..." is a statement of fact. "I'm going to tell you how to explain...". The "I'm going to tel

I think there is a semantic difference. To me, "How to explain the..." is a statement of fact. "I'm going to tell you how to explain...". The "I'm going to tell you" is unwieldy for the title of an article, so it's omitted. "How do you explain the..." is a question. Saying "I'm going to tell you how do you explain the..." sounds ungrammatical.