Yes, that's correct. They're not idiots and realize that spinning up FreeBSD instances in EC2 can be very useful for development purposes -- the largest EC2 instances can run a buildworld very very fast -- but they have no need for FreeBSD/EC2 for their production workloads.
Netflix uses FreeBSD specifically for their custom-built CDN/streaming servers, which are hosted directly with ISPs … not on AWS. Their user-facing catalog app, however, runs on Ubuntu servers hosted on AWS.
At least that’s what I recall reading here on HN.