Why water is not acidic?

When we were in high school, we learn the chemical properties of halogen elements. The strength of acidity of HCl, HBr, HI, decline in that order. Surprisingly, HF is not the strongest acid. It is a rather weak acid. The textbook noted the fact, but without explanation. I asked around and got no answer.

Similarly, H2S is acidic. Oxygen has a stronger pull to electrons than sulfur. Water, H2O, should be even more acidic. But water is neutral.

For HF, the attractive force of F atom, being small, is very strong. There aren’t  many free H+ available. So, HF is a very weak acid.

Similarly, the attractive force of O atom, being small, is very strong. There aren’t many free H+ available. So, water is neutral. (You might also claim that the small amount of H+ is neutralized by OH-. But you need to explain why H2S doesn’t enjoy a similar property.)

The answer turns out to be very simple. But I figure it out just now.

Small atoms, such as H, C, N, O, play central roles in building life. To understand life, it is crucial to understand chemical properties of them and their molecules, such as water.