They were attacking the market in a sense as it relied on latency of information to determine prices. Certainly I'd dub these gentlemen posthumously as hackers, maybe they were the first.

I agree. As well, these things were called semaphores rather than mechanical telegraphs.

Furthermore, the British Navy sent many cannonballs in their direction during the Napoleonic Wars, which were long before 1834. That might count as a cyber-attack.

Plus considering there was a manuscript on cryptanalysis written as early as 800AD (IIRC), it can hardly be considered the first. Additionally, I'd consider cryptanalysis (ie, decoding messages not intended for you) more of an "attack" than this nonsense.

I'm sure there were a million other "interfering with communication" instances throughout history,why they picked this particular one is totally baffling to me.

Yes, that does seem like the wrong term. Maybe "network hack"?

Phreaking.

Agree. Sounds like "piggybacking."