The posts here can affect the entire network. Plus, if you have the association bonus you should be able to know how downvoting works and not be likely to abuse it.
Here is the reasoning from the original FR:
This is to be expected for regular Stack Exchange sites as you are expected to be involved in the community before you are deemed knowledgeable enough to be part of the community voice. However, MSE is different because you are voting for the entirety of the Stack Exchange network and you shouldn't need to be active on MSE itself to have a voice on changes to the entire network.
This is especially important for questions like A New Code License: The MIT, this time with Attribution Required because it will effect every network to do with coding at all. This was brought up in this highly upvoted answer.