One of the points ESR listed with hackers' ethical considerations (sorry, I can't find it ATM) says roughly that "No problem should ever need to be solved more than once."
The GPL forces people to look away, to keep shopping for solutions or to write their own. The GPLed solution which could have made their life easier is on the wrong side of an event horizon which prevents them from taking advantage and causes a problem (many problems!) to be solved more than once, because they don't wish to go there and stay there.
Code without that one severely inconvenient restriction is code that can be more useful to more people, if that matters to you.
edit: Hey, search engines are neat. http://www.catb.org/~esr/faqs/hacker-howto.html#believe2
Oh, look! Item 5 in that section is all about how full of shit I really am, how droll... But the point stands. I once put a project on the shelf and promptly forgot about it because I needed some combination of µSD over SPI and FAT32 and 4-bit HD44780 LCD interfacing and these were doable with different already-published libraries for AVR chips, but if one of them was GPL then my whole project had to be 1) GPL, which I didn't want, or 2) never shared with anyone, which made it seem a waste of time. Arguably, I ought to have banged something out, made anything work, and then kept shopping for a proper replacement for that one lib, so it's still my fault, but the restriction was, and still is, somewhat demotivating.
That "event horizon" you're talking about is one that stops people from taking code that already exists, building on it to solve more problems, and... not letting anyone else use it.
I, too, believe that no problem should need to be solved more than once. The GPL is in part a tool to help ensure that.
I want to give everyone all the same freedoms that the GPL guarantees, and I want to include freedom from the GPL. I don't want to be afraid of wrong people doing wrong things so that I'd be spending time and energy trying to stop them, especially not if it interferes with doing useful things for anyone. The Sqlite blessing is really neat.
Is it selfish? Perhaps, in a way. I'm sure there are some who genuinely value the freedoms granted by more permissive licenses for their own sake, and who are principled enough to never take advantage of that and lock up the results. You may be one of them, and I can respect that position. I'm willing to bet most of those who strongly avoid the GPL are not.