Nobody thought to cut Spock's emotional reactions when that footage was incorporated into "The Menagerie". I never had a problem accepting that Spock might be a little less stoic earlier in his career.
I suppose Spock was still "in development" during "Mudd's Women" and "The Enemy Within" too.
What sort of logical unemotional being regularly trades barbs and insults with Leonard H. McCoy, who is possibly the most illogical emotional being in the universe? ;)