He's right on a couple of things, which makes it easier for him to use a sleight of hand to jump to the conclusion he wants.
In a nutshell: the Bible has way more to say about money than it does about sex, that the Bible is the map of the terrain, not the terrain itself, and that if you're having a hard time reconciling reality to what the map says is reality, then perhaps you're holding the map upside down.
Another nutshell reading: If the map says you're in Texas, but you'd rather be in Florida, then the map changes to confirm that you're really in Florida, just as you'd hoped.
If he'd stick to saying one sin was as bad as the next, he'd have a point. But he seems to be saying the volume of material itself somehow makes one thing grave sin, and another as if it'd never been mentioned at all.
The tax code is infinitely more complex than any federal or state murder statute. I doubt anyone would argue that the tax code being more voluminous means cheating your taxes is far more terrible than murder.
It has just as much to do with the difficulty and application of the topic.
I couldn't read all of it though. The first link didn't work for some reason, and I didn't see a link back on the 2nd page.