I thought that говорят implied "they" because it's referring to multiple things/people saying something.
"Говорят" acts like "it is said" in multiple case and direct (non-reflexive) form. There is no "they". And it means "they say...". But "Они говорят..." means "(Bob and Todd, who was mentioned before) say..." only.
And this is just example of "mentality of words".

Говорится, что снежный человек последние видели в лесу близко к мою дому.
Говорят, что снежного человека недавно видели в лесу близко к моему дому.