Ta'anis 23a - Choni Ha'magal

The Rambam (Talmud Torah 6:14) lists 24 things that someone is put in cherem for. #1 is for kavod of a chacham and #14 is one who brings the public to chilul hashem. The kesef mishnah explains that the source for #14 is the story with choni where shimon ben shetach says that he should be put in niduy bec. if this were like the days of eliyahu where there would be to contradictory oaths that would inevitably bring to chilul hashem. The Mishnah L'melech points out that Rashi (both in the mishna and gemara) take an alternate approach that the niduy was for kavod ha'rav i.e. being matriach Hashem excessively. The Mishnah L'melech asks, that since there was an issue of kavod ha'rav in the actions of choni, how can this story be a source that there is justification to put someone in niduy just for bringing to chilul hashem alone? Although he brings down an answer, he says that it is not "kdei sviah". Any thoughts?