I don't think this is right. The terms of the IP non-assert clause say nothing about patent trolling. What the clause says is actually pretty simple: no customer of AWS services can assert a patent claim against Amazon related to an AWS service that the customer used--and that is equally true whether you have a legitimate patent infringement claim, or if you're trolling.
The article's open source point is perhaps a bit tendentious (or underexplained), but, contrary to the impression you convey, it is only a very small part of the article. The bulk of the article raises entirely real issues.
Edit: I think the open source issue is this: if an AWS customer uses open source software (or, more simply, if an OSS project is hosted on OSS) how far up the user/employer/vendor/contributor chain does the non-assert clause reach? If I contribute to project X, which is hosted on AWS, do I become a party to the non-assert clause? What about my employer? What if I contribute to the project as part of my employment? I think this concern is probably not too significant (particularly since it only bars someone from asserting a claim related to the AWS service used), but I don't think it's fair to call this FUD, much less to call the whole article FUD because it includes this as an ancillary point.