Mr. Cameron just happens to be right ...
Of course he's right to note that, notwithstanding anything Apple may or may not say, the data they collect serve to uniquely define individuals. And of course that's precisely what makes such data valuable, and hence interesting to collect.
The question of who Mr. Cameron is working for is of course totally beside the point. The only thing that counts is what he says, and what he says is accurate.
The data collected by Apple go a lot further than the data collected by Microsoft, simply because Apple collects its data from a phone, not a computer. That matters because a phone contains a lot more data about you than your computer.
Things like: occupation, language, zip code, area code, location, and time zone aren't collected by Microsoft. At most they get an IP address, which is typically a dynamic address provided by an ISP, and a MAC address. They don't get a physical location, and certainly not in real-time. And they can't reconstruct your travel pattern either. Phone operators can. And now Apple has reserved the right tho shop that sort of information about people to whoever they like.
Spot the difference?