The standard terms allow anyone to reproduce this data, providing that certain conditions are met. One of this involves the display of a graphic indicating that the data has been syndicated from the NHS, which is obviously not possible with a service that has no visible user interface, which (partially) explains the need for an Amazon Echo-specific license agreement.
One might object to the fact that Amazon was able to negotiate a custom agreement that is not available to others, and it would certainly be good if other voice-oriented services were able to access the data on similar terms. Beyond that, objections to Amazon having access to this data must be rooted in either a) dislike of Amazon for other reasons or b) dislike of the general principle of open data. I think it's mostly 'a', on the basis that Amazon doesn't pay 'enough' tax, but ends up turning into 'b' as the suggestion is made that perhaps Amazon should pay for access to data that is otherwise open. It's a confusing mess of an argument.