Of course it can. Contracts and other agreements limit your rights in some way. That's the whole point of signing an an agreement: mutually agreeing to something that isn't guaranteed by any other existing law.
I have some idea of what I am talking about, because I do work for a large online forum, where the legal department has made it very clear that we do not need to honour requests by users to have their accounts deleted. We keep the right to display their contributions, because they have granted the forum copyright on those contributions. Not an exclusive copyright, mind you. We only have to anonimize their accounts and contents.
There is an inverse to the disease described in that article: the idea that someone with a lack of expert knowledge cannot possible say things that are correct, just because you disagree with him.
The following:
[something] cannot override statutory rights.
is a blanket statement, to which anyone can find counterexamples. You're just not trying, because you are too focussed on your original point.
In general, I know jack about the practice of law and I know it. However I know about this specific instance, because lawyers told me how it works, and I actually do know a bit about theory of law. I'm trying to explain to you how this specific practical fact of law could come about, based on theory of law. Specifically, the fact that laws fall short, for instance because of ambiguity and because of conflicts with other laws. Even the basest constitutional rights give rise to such conflicts, which is why judges are needed to interpret laws. Quite a few laws are around, specifically to stop gaps in other laws. Example: the first sale doctrine.
As an example of an obvious shortcoming: you are allowed to go wherever you want in a public place. The law specifies no limitation on that. However, there certainly is one very certain limitation: you cannot occupy the exact same space someone else is already occupying and you cannot get him to move by claiming your constitutional right to occupy that bit of space. It would be silly to actually codify such limitations in the laws, because their number cannot be exhausted. However, it is a very clear limitation on one of your fundamental rights. This is not my intelligence speaking: this is my knowledge of fundamental problems in philosophical theories of law and their very practical implications.