Strange laws from a western perspective, indeed. I never knew about them. It's certainly something they'd have to change if they'd seriously wanted to join the EU (which I doubt meanwhile).

OTOH, we're not here to judge but to find solutions. We will not find a solution for a Nokia marketing decision based on whatever factors we don't know.
But the community can provide a Turkish UI and even several Turkish keyboard variants for the onscreen-kbd to make the N900 more enjoyable for those Turkish speaking people who live in countries with more liberal laws. (Or to make it more attractive to import the device to Turkey.)

Once a framework is in place, you could use the standard mechanisms already in place to translate third party software.

I realize there's more ppl than I thought here who speak Turkish as their first language. If one of them could just set up a project and do the coordination work, I'm sure it could be done in relatively short time. Sooner than MMS-support, I'd guess.