They are right. They know the speed link is from your modem to their gear and that's the speed they deliver. Once you are off that link, speed plummets to whatever the internet happens to be going at with the slowest link being the bottleneck.
Here's what many can't wrap their head around. If the server that is sending content to you is on some other network, then you can't get FIOS speeds. That's the SHORT version.
The Cnet speed test is not a test of Verizon's speed but from of the total link from here to there.
I have been pulling 15MB readings on CNET's broadband speed tests for months. The problem is... I have a 35MB plan. I have used tests from other sources...and all are consistent with CNET.