I agree, it is incredibly annoying.
I touch type and I know how to spell.
I rarely make typing mistakes, and when I do make a typing mistake, I see and notice it because i'm staring at the freaking screen.
(Conversely, when I don't make a typing mistake, and Google randomly changes my search, I don't notice, because I didn't do anything).
Particularly when you are searching for something and google changes it to an off by one that looks similar. For example, today i was trying to find libbcrypt, but Google kept changing the result to libgcrypt, which is not what I wanted, but they look similar enough that I clicked through some irrelevant results before I noticed.
Searches that would have taken one attempt, if Google had done what I told it to, now regularly take at least 2 searches.