But the beauty of Decred is the hybrid block validation where stakers have the final say in validating mined blocks. This maintains decentralization while keeping the security of a network with more hash power. I can only see Asics as a good thing for the future of Decred.
How exactly do I decide what blocks are valid when voting? Why would I want to vote any block as being not valid? Not to mention that putting a "no" vote in a block I am called to vote would result (if the no prevails) in the block becoming orphan and therefore no stake reward for the ticket.
Also the whole voting/staking system is automatic. My tickets are called to vote and they do. I never choose any yes or no for the blocks, I don't even know how. I only know how to vote for other stuff when available, like the lightning network or ticket price algorithm change.
Finally, with staking pools active and used by most, you could argue that staking is also quite centralized.
I would like to know this as well. On the Decredition wallet, I don't see any option to vote "No" on a block.
Let's not mix things up. OP asked how to decide on the validity of a block. You're asking how to issue a "no" vote.
So, for the block validity question: that's done programmatically. Yes, PoS votes get the final say if a block is valid or not. This isn't something that someone running the node has to actually make a decision on for every single block. There is logic which can be defined such that if certain preconditions for a block are met, you as the PoS miner will "choose" not to include it. Also, I'm pretty sure you still get a vote reward even if the block doesn't become part of the main chain (someone correct me if I'm wrong).
Voting "no" is different. Once we things to vote on, you'll see in the wallet your vote options. Typically, your options are: yes, no, or abstain. Just so it's clear: this isn't voting on a block, this is voting on an improvement proposal.
Pro resource: https://voting.decred.org/