Re: "but also seems you weren't any better as a manager"
"The issue is it was impossible to held him to the deadlines. He agreed on them - and often I allowed him more time than a skilled developer needed - and then utterly ignored them, producing different excuses. Being kind and remembering him how important it was for him, the team and the company to deliver good code in time was utterly useless."
You're sort of posing a false dichotomy here, though. There aren't only two choices: 1) scream abuse at people, 2) be kind to them and work around them at all costs for fear of upsetting their precious sensitivities. (In fact, ironically, in my experience it tends to be the case in broken situations that important people get to yell and scream all they like, while everyone else has to bend over backwards to not step on their precious toes).
It's perfectly possible to point out that the developer in question is not doing the job properly, and to progress from there to formal performance review measures and ultimately disciplinary measures if there really is a long-term problem, all without being abusive, hurtful or personally disrespectful. Millions of people manage to be involved in processes like this every day. It's not rocket science.