Speed: As specified in the article
http://www.gnu.org/philosophy/javascript-trap.html you can specify the
license of a script with one comment. One comment. I don't see how this one
comment would impact rendering speed, especially if you send it gzipped. Now,
I'm not sure if LibreJS will account for that, but Stallman's article offers
it.
Copycats: Plenty of sites make have freed their source code. Where are all
the Reddit and Slashdot clones you seem to think exist? For that matter,
where are the ones that matter? It is trivial to copy a site that exists,
even if the backend is proprietary. There's plenty of StackOverflow clones
but most of them look like dreck IMHO. You won't get ahead by just imitating
someone else.
If you honestly think any source code you write is valuable enough that every
visitor who happens upon it wants to "steal" it, more power to you.
