If a manager makes a decision having weighed the factors, and some team members disagree, but it's an arguable thing (corporate strategy for instance) and the difference is mostly one of opinion, sure, I agree. Constant criticism of that will get tuned out.
There's also cases where something is just clearly dysfunctional. For instance, if the CEO is constantly talking about how the firm needs to move fast and innovate, but installing a new piece of software on your workstation takes six months and involves three forms, it's fair to say that isn't a difference of opinion (all parties want to move faster and innovate more), that's a failure of execution. Someone, somewhere, clearly feels that this bureaucracy is worth it, but they probably can't defend that given the firm's priorities.
You can phrase that as "this process is great, but we could make it even better" if you want to be as well-loved as possible. My experience has been that this usually leads to an answer of the form "thanks, we're glad you love our service, unfortunately we have many other things we're doing right now kthxbye" - i.e. when nothing is bad and everything is merely a proposed improvement, improvements that might be even slightly threatening to anyone just get ignored entirely. And you can't complain because everything is peachy, right?
Super good point, thanks for that.
Every one of us is sure we know how to do our manager's job better than he does. There are threads every day on HN (including this one) on this. Is it any surprise that managers tend to tune it out after a while?