If sinner's didn't preach, there wouldn't be any preaching.
The standard Bennett is holding up is not wrong. And it is not wrong for him to hold it up. Those virtues are good standards and we should all aspire to them. We should all hold them up, whether we successfully attain to them or not.
If you applied the same "Standard bearer must be perfect" to everything we do. There would be no standards. The US couldn't even advocate for democracy, when things like Palm Beach happen and democratic vote buying occur.
It wasn't so much calling for a purity test as posing that politically this wasn't very strategic.