Why not? Bitcoin is centered around open source software. Should satoshi have charged people to use bitcoin? Not everything has to have capitalistic motives as well, though if theymos wanted to make more money surely he would have planned to charge people to use the software?
You're correct. Open source software is great. However Satoshi didn't pay a development team $1,500,000 to create the bitcoin network & software. There's a big difference in those comparisons. Capitalistic motives aren't necessary, why not keep the software unique to this forum & don't allow others the chance to reap the rewards of a one and a half million dollar software package?
I don't know why anyone would pay this much to use forum software. Maybe in the future companies or organizations wont have to pay anything because of open source software like this one. That's the true beauty of it.
Because they are companies and need massive control and functionality on their websites, and Lithium is the only software on the market right now that offers the extensive functionality that these companies require. People think vBulletin is functional and customizable... well I suggest you take a look at some of the moderation and administration tools on Lithium... simply flawless!