even private servers have something that block bots so why can't ncsoft do it?
Lets look at it from an economics point of view. NCSoft charges a fee for people to connect to lineage 2. Bot programs charge a fee for people to use their bot program to play L2.
NCSoft has to use their monthly fees to run the servers, expand the games, offer customer service, police the servers, market their games, go at conventions, run a website + forum, etc.
The bot program has very minimal and sporadic development and absolutely no support. Got a question? tough noogies.
When NCSoft has their developpers work on a new way to stop the bot programs, it usually takes a maximum of a few days before the bot program gets fixed and it works again.
When a private server does something to block bot programs, the bot programs don't care, because it's not a big enough market share for them.
So obviously it's much easier for a private server to stop all bots since they don't have to continually find new ways to block them every 2-3 days.
Also why isnt Ncsoft threating with legal actions against the [censored] site and those adena selling site?
Most of those companies are located in countries where legal actions would either be extremely complicated or outright impossible. Some countries have no copyright laws, for example, so them ripping off the official lineage 2 server and operating it would be considered legal over there.
Whenever NCSoft believes they have a good case against such companies as private servers and RMTs, they usually go ahead and bring them to court.
The other issue is in regards to what to sue for. For private servers it's easy, esp. private servers that charge a price, NCSoft can say "you have 10'000 customers, so 10'000 x 15 = 150'000$ per month in lost revenues for us".
For RMTs (Real Money Traders), the situation is complicated, because you have to examine how many customers you lost by having RMTs in your game, versus how many customers you would've lost if it weren't for RMTs to support their playstyle. This would make a very complicated court case and since the court would have to be overseas (since most adena corps are overseas), you have to include the judge biases and, by the end of the day, NCSoft would almost have to be happy if the court doesn't charge THEM for the legal fees incured by the "frivolous lawsuit". Which is outright ridiculous, but that's how things work.