The Yiddish expression means that Orthodox Jews, who are in the main the most honest people on earth, are severely let down when some of their number do a kuk!
A great Chillul Hashem is caused when Orthodox Jews, particularly in the US, UK and Israel, even rebbes and rabbis, are found money laundering drug money, property swindles, charity diddles, ID fraud, false claiming of benefits, deliberate bounced cheques, voting fraud, diamond-dealing tricks, postal fraud, not paying workers and suppliers, VAT & tax reclaimance fraud etc etc.
Thanks to computers and stricter sentencing policies, things have tightened up recently, and if these guys are found guilty, they'll serve 5 years at the "Bet Keleh Mar Prison for White Collar Criminals" near Yokneam, which will act as a mighty deterrent to their chevreh.
The Gemara says that the very first question a soul is asked in Olam Haba is "Were you honest in money matters?", and that there is great consternation among the Angels if the answer is in the negative!