First, your opinions about what you're working on are at least as important as your development contributions. Good clients light up when someone smart shows up and pushes back against their dumber ideas. It's unfortunately true that most leaders have unintentionally created social structures around themselves where, for several reasons, they are rarely disagreed with. Someone offering a compelling and assertive telling you not to do something before you do it will be regarded with the passion of a new lover. People inside of an organization are hamstrung by harsh social, political and personal setbacks if they are perceived as disagreeable and frankly, most employees need to believe their founder has a clear vision. Result: no honest feedback.
Second, even if you're totally fine taking a sociopathic view and accept money for work that you know in advance will fail, the people who work for you that trust you to find them projects where they can contribute to something meaningful will become depressed and resentful. They will do terrible work until they leave to find something more satisfying.
Finally, this is subjective but experience has led me to conclude that even the most confident and successful people never "just know what they are doing". Entrepreneurs are plagued by imposter syndrome and the vast majority of decisions they make are confident wild guesses based on incomplete data under stress.
The smarter the leader, the more energy they will put into surrounding themselves with smart advisors. And if you're good at your job, you're one of these key advisors and that's why they hire you: to have strong opinions and give a shit about them and their company.
I don’t really want a consultant who just came in and thinks he understands the whole situation. As consultant you should do the job you were hired for really well. You can make suggestions but in the end you should assume that the people who hired you know what they are doing until clearly proven otherwise.
Answer: you're not a sociopathic consultant, just a client who sees the hired help as a commodity chattel. That's you're perogative, but if you woke up today willing to be humbled, what you haven't realized is that by definition, you're working with below-average consultants who only care that you pay them.
The optimism is that an entirely wonderful future is possible if you accept that you just might be doing it all wrong.
On a serious note it took me a long time to understand that some clients do only want you to execute and do not want you to provide a more holistic professional assessment at every stage.