The congregational elders took steps to create more decorous conditions from then onwards, and many Anglo-Jewish communities followed their lead in preferring stateliness to celebration. This was still the norm three centuries later, to the extent that some-one said of the Hampstead Synagogue that Simchat Torah was as mournful as Tishah B’Av.
My own Hampstead incumbency was the time when some quite restrained dancing with the Torah was introduced, though not without the stern disapproval of some of the congregation.
It is a good job that Pepys did not attend a Purim service; I have no idea what Purim was like at the Spanish and Portuguese Synagogue in his day but we are all well aware that in most places it is marked with considerable exuberance. Some say it is the time when people let their hair down, but I personally find that a problem now that I have hardly any hair left.
The serious question is of course whether there is a case for religion being “absurdly performed”. There are two answers. The first is that we are not without our solemn occasions, probably outweighing the times of frivolity. The second is that religion is a dimension of the life of a people, and people have to be able to articulate the whole range of human emotions.