You're linking to commercial services touting them as examples of Amazon being more open than Google? Services linked to are: MapReduce, S3, EC2, SQS, SES and MechTurk.
I think what the article means here is that with Amazon, you can just use it. It's not free or open.. source but you can just access it, understand how it works and use it.
Google just tout they have XX and ZZ but only so-called elite can play with it or even just know more about it. It might end up being crap, no one else than Google engineers will know.
The only way you are going to learn how these proprietary systems work are by working at Google or Amazon. What makes the EC2, S3, etc. APIs different from AppEngine or the 100s of other Google APIs there are? They're all just APIs to proprietary systems (well, except when writing apps for Chrome and Android). You are learning "how they work" only in the most superficial meaning of the phrase.
sigh