While I am not trying to defend the RBI, I will try and give the reasoning from RBI's perspective. Note that I don't personally support these bans.
1) Banks in India do not provide easy ways to do chargebacks. Also, many people are not even aware that you can do chargebacks. I have to manually call a bank and ask them to do so after going through a couple customer service representatives.
Also, consider that a big chunk of the population is coming in the ambit of financial institutions for the first time. Many people are opening their bank accounts for the first time. Many people in India still do not trust the banks. If they see a couple hundred bucks vanishing from their accounts, they might as well abandon putting money into the accounts.
Incidents like Target or Home Depot if happen in India will rock the trust that people have in these institutions.
Banking in India is a business activity synonymous with trust [1]. And in my opinion RBI has done a fine job of it.
2) RBI banned Paypal earlier because it concluded it's not complying with regulatory framework of the country. These regulations are in place for a reason. If they are obsolete then we should campaign for them to be eased. But you don't get a free pass just because you are a big entity.
Paypal as they were operating earlier had to be regulated as a bank and PayPal does not want that to happen. Any entity which provides on-demand payments back then had to be regulated as a bank as per RBI rules. PayPal was basically circumnavigating this regulation so that they don’t have to answer questions to the government about how they conduct business. Also, getting a banking license requires a lot of regulatory oversight. The closed wallets regulations that RBI came out with later was a in my opinion direct response to this.
3) Uber was routing Indian card transactions internationally. They were in essence exploiting a loophole in the regulations. If RBI hadn't blocked Uber, then Olacabs, Flipkart, etc. will also have done the same. This will have directly undermined the 2FA policies RBI has put in place. Forcing Uber to comply with the policies was the right choice at that moment.
4) The proliferation of closed wallets has forced RBI to consider whether removing 2FA on small value transactions will be beneficial.
You should understand that India's economy has only been opened recently. A lot of the restrictions will go away with time. If you think they are harmful then convince the RBI of the same. But these restrictions cannot be removed overnight just because a new startup feels the need for the same. RBI's each decision will have far reaching impacts on the financial systems of the country and they need to be taken with utmost care and foresight.
[1] http://www.rbi.org.in/scripts/BS_SpeechesView.aspx?Id=587
Edit: Added more context for Paypal