Sublime Text itself was very much "inspired" by TextMate back when both of them were commercial and closed source.
The flip side, of course, is that only a limited number of developers can afford the time to write a full-featured programmers' editor with no expectation of recompense. That's not trivial stuff. There are an awful lot of free editors out there, but most of them end up being relatively feature-limited and, at best, "cult hits." Even getting to that point takes years.
(And, while I hope this won't seem too cynical, the pain points Lime's developer describes as his motivation don't strike me as coming from Sublime Text's status as closed source. They strike me as coming from its status as a one-person project. A one-person open source project is theoretically better than a one-person closed source project, but...)
Seriously, though, you do know that there's no such thing as a free lunch, even when it comes to open source, right?
The presumption that he's trying to destroy the original developers livelihood is naive at best.
But we're not just a demanding (less respectful, in your terms) industry, we also are one that's willing to support itself - developers do pay to support each other.