But I keep thinking that this is a limitation of MIT. It's written with the purest of good intentions but without any way to prevent bad actors from exploiting that.

I wonder if there's a better kind of license that provides a close level of freedom but would prevent some of the most obvious exploitations (e.g. packaging and selling the code, or reposting on a site with advertising)?

There's copyleft licensing like LGPL but perhaps that goes too far in the other direction and besides, it seems to be very unpopular amongst web developers so I'm afraid if I release any LGPL code it won't get used much or attract contributors.

Is there a happy medium between these?