I believe there is a difference between gold-standard perfect code and just making "beginners mistakes".
It costs almost nothing more to write "event" instead of "ev" or "removeElement" instead of "remEl", but it makes the code much more readable. You might gain 1s for writting remEl instead of removeElement but you will loose more seconds in the future trying to remember what remEl stands for, or having to check what abbreviation you chose for that function.
It's just something programmers learn with experience (even when working alone) : abbreviations are a false good idea, and people are just pointing that out.
It costs almost nothing more to write "event" instead of "ev" or "removeElement" instead of "remEl", but it makes the code much more readable. You might gain 1s for writting remEl instead of removeElement but you will loose more seconds in the future trying to remember what remEl stands for, or having to check what abbreviation you chose for that function.
It's just something programmers learn with experience (even when working alone) : abbreviations are a false good idea, and people are just pointing that out.