I see what the problem is.
Others like me whose native language is English have noticed that while the application and documentation are in English, it is not the dialect of English spoken by people who speak native English.
In other words, the English used in the application and documentation does not make sense to Americans and British - because it is a different English.
To a person who is American or British, the phrase "Replace All" means to replace all of the words at once. The way the process works in that video, the button should instead be labeled "Replace Next" or "Replace On at a Time". Others from America and England I have messaged with in here have had the some concerns.