If your job is to tell people they're wrong every day, you're working with the wrong attitude.
Your job isn't to say no, it's to say: "This doesn't work, but how about this?".
Engineering isn't about being a prick that shoots down ideas and be the "smartest person in the room", it's to make those ideas become reality as closely as possible while working within the constraints of what's feasible.
You seem to be making a lot of assumptions, and it's unclear how much direct experience you have of being in a bad situation where the day-to-day job does become saying no.
Some examples that you may be unfamiliar with:
* Working with a manager who is a former dev that likes to micromanage the decisions that their team makes.
* Working on a team that is driven / owned by a product owner who doesn't understand as much engineering as they think that they do.
Neither of these situations are examples of healthy functioning organisations, but they do occur. They are not an exclusive list either, just some random examples from personal experience.
Shooting down ideas may be a symptom of somebody being a prick, or it may indicate that they know why the idea will break the system (even if it closes a ticket or gets a particular feature finished). The ability to propose an alternative can be restricted by just how batshit insane the demand is.
It's not that you are wrong when you say that an engineer should respond "This doesn't work, but how about this?". But that characterization is incomplete - sure it works in theory, but there are many places where it does not work in practice.
Your job isn't to say no, it's to say: "This doesn't work, but how about this?".
Engineering isn't about being a prick that shoots down ideas and be the "smartest person in the room", it's to make those ideas become reality as closely as possible while working within the constraints of what's feasible.