One has to look at history of dance to understand the devadasi system without prejudice.
When cavemen wanted to communicate they shouted and moved their limbs in ways to depict the happening - like a forest fire or catching of a wild animal or celebrating birth or death...
This action was region, geography specific - like men near a sea would not know killing of tiger and tribes living on mountain tops would not know existance of sea and fish.
As the group became little more civilised, they started to use these same actions to entertain themselves - in the evenings. Everyone used to participate and slowly, they started developing a pattern, a rhythm for their actions.
A time came when the ones who could do better and more vibrant actions used to get centre-stage and those who could not used to sit around and just clap, but, participating at the same time.
Now when groups used to move from place to place for various reasons, each group wanted to show-off that they could do better. Hence, the best of the lot used to be assigned this job of developing the actions, motions, rhythm etc.
Classical dance would have movements based on the region from where they originated - you would not have actions that are in Manipuri in Bharatnatyam. The banging of the leg on floor and Araimandi is supposed to be influenced by the land and its cultivation - women banging their feet on the ripe paddy. Once it is stylised, it became basis for the dance of the region.
Amongst the people, who could do a particular task in a more effective way became the ones who would do that for generations - as teaching was through Guru - Sishya tradition, and who would be a better student than his / her own daughter / son? Hence families got earmarked for each task. We will get into arguments on Varnashram from here!!!
As civilisation progressed, the tendency to outsmart others and to show that their group is better than others also grew. The communities decided on places to meet during village meets and perform - which became a complete entertainment. What other place is better suited for such activities than a temple where worship is done and many village matters get discussed. Then dance became part of the worship and like Punditjis, Poojaris maintain cleanliness ( madi in Tamil) these dancers also had to keep themselves clean - meaning, not to mingle with common man.
Royalty was equated to God everywhere, just out of (fear) respect. Hence, the dancers used to be given away to God / Goddess and they cannot have relationship with mortal men. One out of every 10 women dedicated to God used to have relationship with the royal court that patronised the group either out of desire or out of compulsion.
Naturally, royalty exploited them ( like they exploited anyother worker under them ). Again there had been many benevolent dictators in the course of the history and also that of the other type. You can never have 100% white or 100% black !
With coming of Zamindars and Zahirdars, they took the place of royalty, but the monetary support did not happen. Then the group turned into a lot of immoral activities for sake of money and largely for their survival.
Mrs.Arundale's contribution came in time to retrieve the art which was becoming extinct. Art had undergone deterioration over a period of 70 years and hence the songs on God had become songs on men who supported them.
Rukmini Devi refined the poses, body movements, got many compositions corrected to include only God's name and changed the way jewellery was used by them - during the decline, they were used only to show, how much patronage each one got - and not to beautify oneself.
Hence, she reduced the number of jewellery worn, changed the style of costume from saree to pyjama type costume and made Nattuvanars sit in one side of the stage (earlier they used to move alongwith the dancer on the stage ) so that the attention is on the dance and not on so many people moving along.
That was a great revolution she brought in the mind-set of people, that the purpose of dance is not immoral - but it is divine.
Even today we have Bhatjis like the one we met in Thiruvalanchuzhi Swethavinayakar temple and also those whom we see in Srirangam temple. Does that mean the vocation they are in and the tradition of them becoming Bhatjis in temple is bad or the persons or bad / good?
My point is, had there been no Britishers, the artists would not have become so commercial and 5 out of 10 of them would have upheld the pure art for art's sake.
Somebody was practising dance here in this cave { a dancer in my team tells that the steps are not followed today and very tough to practice though. She cant interpret them meaningfully with present dance forms) during the cankam age. And this is the first ever written proof of such things and that too in Tamil!!
I think the system of devadasis got corrupted much before the british arrived in India or it was created to be like that. Perhaps it was a way of living and it was normal for people in those days.
Rajanarayanan ( karisal kattu thatha ) in one of his books portraits how a few village men decide to punish a criminal on a "kazhu" The criminal dies a horrible death after 3 or 4 days on that "Kazhu." It looks it was so common to punish criminals that way - a few village men could decide that and there was no government to challenge their decision!!
So we did not have any modest laws. Our country had extreme limits of existance.