How does an ordinary user affect the decisions? I simply don't get it. If you're someone who protects the network, you ought to vote for a change, you're the transactions' validator. An ordinary node that doesn't help the network doesn't have an opinion. I could create dozens of nodes from different parts of the world and maybe even dominate in the majority of the tor nodes. What am I doing after all?
Yes, I follow the consensus rules by myself, but the protection of the ecosystem isn't done by me. Why should I vote and how many votes for a change do I deserve?
Okay, so firstly, miners are dependent on the users that are using Bitcoin, because they are the ones that sustains the market for Bitcoin, agree?
Users do not vote using nodes, I've never mention that. If users do not run their own full nodes, then whatever rules that they're enforcing is dependent on the server that they are relying on. Full node always have a say in whatever rules that they want to follow, which can be defined by their user. If there isn't a point in running full nodes, then no one is really validating for themselves and the economic majority would rather just go with whatever rules the miners want to implement.
There is a misconception that miners actually vote to implement any new rules or not. They essentially are signalling support for it, or rather compatibility but do not decide which rules get implemented or not. The full nodes which comprises of the economic majority are directly responsible for the set of rules being implemented. As I have said, again Segwit would've never happened if users have no say, or if there isn't a way for users to implement the rules that they want (which, in Segwit's case was for UASF and Taproot which would've been forced LOT).
Which really brings me to the point that most users should ideally be running full nodes, and actively use it.