How gentle should a DM be?
I haven't had (m)any issues with players expecting or needing coddling. I suspect issues similar to those the OP described were due to differing expectations about the rules, tone, and/or style of game, i.e., the GM and player were operating under different assumptions. A GM can mitigate a lot of these misunderstandings by being very clear about any house rules, etc. they will be using and/or the style/tone of the game in question. This is commonly referred to Session 0 and/or Social Contract.
Some players want to know that creatures will behave exactly as described and won't mechanically deviate from rules as written. Some players don't respond well to player agency being taken away, even if it is a result of their own actions. People play RPGs or different reasons and find different things fun.
All that said, there are times when you are just going to have clashing personalities or playstyle differences that won't surface until the game is underway. In those cases, it's best for all sides to part ways rather than labor on in the misguided hopes you are going to change someone else's idea of what is and what is not "fun".
FWIW...I've only had two players flip-out and rage quit a game in the 10 years I have been running games on RPoL, so it's not that common in my experience. It happens, but very rare.
This message was last edited by the user at 20:29, Mon 02 Nov 2020.