OK - I can understand why Elastic would cripple services from other providers that Elastic aren't paid for, such as Amazon's hosted service ( that's managed by Amazon ).
I can't understand however, why Elastic would limit features when they're being paid for, just because the payment is coming via the AWS Marketplace instead of directly to Elastic. Yes, it's slightly less crippled than the Amazon hosted version, but it's still crippled.
What adds injury to insult here, is that where the option for APM is normally shown, it's simply missing. If there was some text there to say that you hate Amazon, and don't want Amazon customers to be able to pay for your features, I could at least have saved the hour I spent re-tracing my steps trying to figure out where I missed the step to enable APM, only to find out later in some obscure part of the manual that it's not available on AWS.