Why do you want to discourage posting? If no one votes it up then it wont be very profitable and that would discourage it would it not?

I think the developers are taking a sort of gamble. They are betting that if they rate limit that the quality of posts will go up. I'm not entirely sure that will happen but it could mean less posts which could make curation easier. 

But what effect will it have on the user experience? We don't know. What if new users complain about this change after it's implemented? If most of the money the new users make is from commenting then if you limit that then you limit their opportunity for rewards which doesn't seem like it would help.