Not true at all. Cryptography Research has patented most of the implementation techniques required to do hardware crypto without being susceptible to differential power analysis (btw: that? My favorite business model ever!). That was almost pure systems research.
Strong disagree. They found the vulnerability. It is a remarkably interesting attack. Without their work, we'd just be silently vulnerable to the problem. I think (for instance) the DPA patents are a decent example of good-faith patents.
RSA was patent-encumbered for a long time too. You can formulate a similar argument about that. "RSA makes systems safer [ed: no it doesn't, but continuing...], so it's wrong to allow it to be patented".
Something as arcane as DES is not a "natural law". Crypto algorithms aren't pre-existing (show me a naturally occuring physical process that can be described by a crypto alogrithm), they're not obvious to even experts in the field, and people spend a lot of time trying to get them right. That's the very definition of patentable.
[I know DES isn't patented, and there's plenty of good reasons why you don't want a patented crypto algorithm, but I think they certainly qualify.]