G Princip was a dumb guy who was used by Serbian military intelligence who were trying to incite violence for their own ends. The chief of Serbian intelligence Dragutin Dimitrijević had extensive experience with murdering rulers: he played a key role in the 1903 Serbian coup, where king and queen not merely murdered, but butchered with body parts thrown onto the street. Dimitrijević financed, radicalised and guided G Princip.

Dimitrijević was key part of Serbia’s power structure at the time.

It seems to be the case that the Russian military attaché in Serbia, Viktor Artamonov, financed Dimitrijević plans. Whether St Petersburg knew about this is unclear, but why would Artamonov use his private money to pay for foreign terrorism?

Russian intelligence had been able to read Austro-Hungarian diplomatic ciphers for a while before the war, so it is likely that St. Petersburg was aware of what Vienna’s probable reaction to the assassination would be.

So no, it wasn't just G Princip.

Today organisations like ISIS use dumb and angry youths like G Princip.