The Orthodox nobility had the same rights at first. But, as you say yourself, almost all of them have switched to Catholicism over time. And the reason for that was that it was the only way to preserve both the rights and the social standing in the long term.

As for nobles not carrying out religious persecution, I don't even know what to say. Local magnates were the main drivers of the religious persecution of Orthodox Ukrainians and Belarusians. And sure, that persecution was often economic in nature, but it was also very clearly carried out along religious lines.

I'll grant you that religious intolerance in Poland was primarily between Catholics and Orthodox, rather than Catholics and Protestants as elsewhere in Europe. But that's to be expected from a country where most subjects are either Catholic or Orthodox, no?

EDIT: I suppose our perspectives are so different because we're focusing on different time periods. My take on this is that early Polish-Lithuanian Commonwealth inherited many of the political arrangements of GDL, and tolerance was one of them. But as the center of political power shifted over to Poland over time, they were weakened.