I disagree with you there. There's a big difference between "Benefit Fraudsters", i.e. Fraud, and using loopholes. That's the difference between tax avoidance and tax evasion.
The original point that cameronlite made is fair enough. Amazon didn't pay zero corporation tax because it committed fraud (at least it appears so), it did so because the law did not require it to pay corporation tax. Some people might consider that "broken", as cameronlite termed it, and others might consider it to be done intentionally.
The point is, even if I think the system is broken, I'm not going to adapt my behaviour to fit in with a mythical concept of moral taxation that has no definition. That's very different to wilful fraudulence.