First off, this advice only applies when you are getting feedback from non-drummer musicians your respect/trust/are usually right about shit. If they are giving you things that are fundamentally off, acknowledge them and do what you must so you don't argue your way out of a gig - then do what you want.
However, I have found that often times non-drummer musicians will give feedback that is at the heart actually sound advice, they just say it wrong.
To address the specific feedback you got - think about WHY the piano player is giving you this feedback. Is he just a stickler? Is he really THAT obsessed with hi-hat placement in general? Or does it just feel "off", like you're not emphasizing the 5 enough, and he is suggesting (albeit poorly) a way to fix the problem?
An example from a recent playing experience of mine: much to my chagrin, I am discovering how much of my default playing tends to be "on top" of the beat, rather than behind. The lead singer/guitarist, who is a great musician but has pretty mediocre time, kept saying "play slower, you're rushing it". Which is fine advice, except he was completely wrong - I was playing it precisely at the tempo he counted out, just my note placement around the beat was improper. After the other guitarist explained to me what he was trying to communicate after practice, the feedback I was getting made much more sense.
If you're doing it right, you're always going to be playing with people who are as good/better than you are. Trust that there's at least something right about what they are trying to communicate, and do your best to decipher what that means exactly.
As you grow and begin to play with more people, you'll realize that most times your feedback will be in the form of vague, emotion-based descriptions, ex: "this feels x, y, z, can you make it feel like a, b, c?". Paradoxically, you'll also get feedback that's specific to the notes played in your composition, but what they might not realize is when they say something like "that's too busy/loud/aggressive", they really just mean it FEELS too loud/busy/aggressive. You could play the exact same drum part in a different way, and it might feel great. In both cases, it's your job to address what they MEAN rather than what they SAY, and fix the problem.
Sorry, went off on a tangent for a second. What I'm trying to say is more about how you deal with the feedback, rather than an issue of who's right.
It's always difficult (for me, at least) to not want to butt heads or prove that you're right, especially when you ARE right and you know it and everyone else knows it! However, in a situation where you're dealing with egos as delicate as those of most musicians, it behooves you to always avoid binary discussions of Right and Wrong. Try and get to the core of their feedback, and address their base concern, or at least do what you can to make them feel heard and like you care (even if you don't!).
Hope that helps!
