Bring it up in the Retrospective.
While your Product Owner's initial axiom is correct from an Agile standpoint, I would argue that his logic following from it is flawed. Here is how I interpret your situation:
- There is a problem with the processes/tools.
- We do not know whether or not there is a problem with the people/interactions. We also not know if there would be a problem if those interactions changed.
Therefore, meet in the Retrospective to clarify that second point.
From the Agile Manifesto:
Individuals and interactions over processes and tools [...] That is, while there is value in the items on the right, we value the items on the left more.
If problem is detrimental to interactions, do address the problem. If addressing the problem would be detrimental to interactions, do not address the problem. If addressing the problem would be irrelevant to interactions, then do address the problem.
After all; there is value to the items on the right. The only time those goals should not be pursued is when doing so would be actively harmful to the goals of the items on the left.
Bring it up in the Retrospective, then react accordingly. This would also be a great place to brainstorm possible solutions, if it is determined to be a problem that should be addressed.