His email is available on his profile, so he essentially already shared it for free...
I agree that it's not exactly free because it has a value, just like your comment right now has one. However it doesn't represent a monetary loss from you (just like your comment right now), which I believe is what he meant by free.
If you believe your personnal email and phone number has a value higher than this ebook, than yeah, don't exchange them, that would be absurd.