Anon1, where do you see any oaths in the first place? It’s not the Pashut pshat in the Pasuk. But it is in the Gemara, when it is discussing Amoraim.
As to your second point, the two oaths are unrelated. One is not to rebel and the second is not to go up en masse.
According to your logic, that it only applied during Bais Rishon, who was it about? Galos Yechonya?