You are a guest here, I am a guest here. The staff can ban you or delete your threads for any reason they want, it is their service. If you don't like it, you could always post nonsensical rubbish on your own forums, but then nobody would be around to see it. Why do you care about someone else's thread being closed anyway?
That's a bit of a non-answer actually, yes it's true that the mods have the power to close down a thread for whatever reason, but in reality they don't close threads unless a rule was broken.
I've personally never seen any mods abuse their power, I've seen a lot of claims that they do, but every time they exercise their power, it has been in good faith. (At least the times I've seen it happen)
This particular thread was closed because:
ATTENTION: Due to the bounty incentivising posting on the ANN thread (which is an on-forum altcoin giveaway in any and all definitions), this thread is locked. There is zero tolerance for those blatantly breaking the "no on-forum altcoin giveaways" rule.