Mining nodes do vote on what is valid or not, but don't have as much of a vote as a large investor or an exchange.
1. Investors dont 'vote'
2. exchanges dont 'vote'
Nodes competing to find blocks and then building upon them 'vote'.
[1] & [2] make choices on predetermined outcomes.sgbett has been explained multiple times why he is wrong and how non-mining full nodes still have all the power but is making a nuanced argument that Full nodes who don't mine simply don't vote because developers defer votes to miners for soft forks and hard forks as a signal to accept a proposal or not. This is purely coincidental due to the limitations in approximating an accurate vote among economic full nodes and because of this we are left with an interesting attack vector some have already committed to exploit during a hard fork.
Way to take my comments out of context. Pay attention to the nuanced distinctions I am making. There are different forms of votes being expressed. Non - mining Economic actors/nodes can quickly cripple the miners if they so decided to.