I came across this phrase is a translation I’ve been working on:
The gist of the sentence is that the guy is a conman so he looks down on petty thieves and pickpockets. But on the first read it didn’t make sense, as 「不恥」according to the Taiwan Ministry of Education website it means “not to feel shame,” as a literal reading of the characters might suggest:
But after some searching and. Some consultation with coworkers, I discovered that Taiwanese people often use 「不恥」in place of 「不齒」，which are essentially homonymic antonyms. As the former means to not be ashamed of something (不以為恥) while the latter means to be ashamed to be associated with (以之為恥), this can cause some confusion for second language speakers. However, likely due to their identical pronunciation, 「不恥」has seemingly adopted the same meaning as 「不齒」in the lexicon of contemporary Taiwanese speakers.
In this Chinese language blog post on the subject, the blogger points to a spoken statement by embattled legislative speaker Wang Jin-pyng, calling the Prosecutor General Huang Shih-ming shameless, in his attempts to smear Wang in an influence peddling case – which many see as part of Ma Ying-jeou’s campaign to get Wang kicked out of the KMT. Wang said that Huang’s behavior ling2ren2bu4chi3 [literally: make people feel ashamed to be associated with] (ㄌㄧㄥˋㄖㄣˇㄅㄨˋㄔˇ) which was interpreted by various newspapers as either 「令人不恥」 or 「令人不齒」. He also points to the fact that what was originally a mistaken use of 「不恥」 seems to have taken hold, given that it comes up quite commonly in search engines in set phrases in which originally 「不齒」would have been used. For those who want to understand why Ma is going after Wang, you can read a bit about it here.