Wolf,
It never really got much better, besides for those good years during Rebbi and Antoninus. During the time of Rebbe Yochanan the empire split. That is why the Talmud Yerushalmi ended then. They couldn’t continue learning the same. They were still called Malchus Harisha many generations later.
This is all, of course, besides my point that there was no fright of censoring in the early days about anti-Roman remarks in the Gemara. So, if Chazal tell us that we mourn the Talmidim that died because they didn’t honor one another enough, then that’s exactly what it means. And when Chazal actually mourn the Harugei Beitar they didn’t hide it. And when they tell us that the Bracha of Hatov Umeitiv is because the Harugei Beitar remained whole they didn’t hide that either.
I didn’t question the veracity of Chazal’s words. My question was if there is any true source that anything significant about the Bar Kochva revolt happened on Lag Ba’omer.