"Playing up to the edge of the line"

Yves Smith of Naked Capitalism was on Fox Business News the other day talking about everybody's favorite investment bank - Goldman Sachs. For some reason, the video is not embeddable, so you'll have to go here to watch it.
The best part of the interview is excerpted below and, in my view, it goes a long way in explaining why the company has been so successful at what they do.

Goldman has long had a culture of understanding where the rules were and playing up to the edge of the line and you know Wall Street has made a practice of doing that for years. The difference is that, over the decades - it really started in the 80s and got worse in the 90s - they were slowly chipping down the regulations. So, what was clearly illegal before is now permitted - though it's not kosher - and this is what is very disturbing to the public. This all doesn't look right - it doesn't make sense to them.

It doesn't make sense to me either.