No, a snarky, rude response to your question "1tbs to a single target is just not possible" that never should have been made, and for that I apologize.
When it is a distributed denial of service attack, you can have an aggregate number of web page request attempts from countless different locations that add up to 1.7 Tbps or more, regardless of the size of individual pipes in the backbone. The bottleneck for some requests may be far away from the intended target server, but the effects are felt none the less.
And the 1tbs never reaches the target, as was implied in the article.