Have you ever genuinely read and understood an entire commercial EULA?
Unless you're a lawyer specialising in such things, the answer will be no.
And probably not even then.
Unless the law requires otherwise, contracts are always deliberately worded to be unclear and difficult to understand, because lawyers make money that way.
Thus the law does need to protect consumers from unfair contract terms, if only because as a consumer, you are never in a situation where you can both demand wording changes and enforce the new wording on an entity like BT.