Don't know what he means, but there were a couple of security vulnerabilities in the past. The German gvt. didn't really address how it was improved, but gave a security certification award to it.
Their problem with the German ID was that cheap readers did not have a keypad, so you'd have to enter your PIN on the PC, which could be infected with a trojan.
It's sad that this myth that "eID is insecure" has stuck around, because it's just not true. Their problems have all been with auxiliary devices or software, not the eID itself.
https://www.ccc.de/de/updates/2010/sicherheitsprobleme-bei-s...