He does not, because the rules are defined to allow some discretion on the part of the host. It's not bending the rules, it's deliberate leeway in them functio

He does not, because the rules are defined to allow some discretion on the part of the host. It's not bending the rules, it's deliberate leeway in them functioning as designed. In particular, if a contestant gives an ambiguous or incomplete response such that it's not immediately right nor wrong, it's up to Alex how soon to rule them wrong or how long to wait for the contestant to supply more information. Besides that, the host does have some discretion on whether to accept a close mispronunciation, and if the judges disagree enough then it will be addressed and corrected at the next break.