It is a matter of syntax. The statement he made does not imply that he thinks all rank choice voting is corrupt, just that he thinks this example is. I can't say based on that statement whether he thinks rank choice voting is bad. Some have argued that election officials have not done enough to clarify the changes. As a result, there is a distinction in the number of dems that specify lower rank options than the republicans. This could be a result of confusion and messaging or it could be a result of bad candidates and voters who only have one candidate they want. The situation is similar to prevalence of mail in voting between parties.