I mostly see the leaders or the product people telling the engineers or designers that they don't understand business—implying that the latter aren't reasonable people who can advocate for things that balance the various dynamics that have been brought up in a meeting, that their view results from only considering the thing technically or aesthetically. It's a hand-wavey maneuver that's always there, said without specifics. This is particularly so given you've provided specs and designs and they rarely show business or market analysis. I've worked with many PMs to propose our work to stakeholders—they swear to the audience they've done the business work, but in preparing the presentation, they just googled a couple very broad things (one example, "the collaboration market is a $70B market"). I've worked with others, who I've tried to learn from, to show or point me to some basics of that analysis and they didn't know.
Product managers and product people in general have very little background in product management. It's not a degree or anything. Sometimes they come from backgrounds that are helpful, but we oddly have junior and entry level ones. This doesn't make that much sense, given they are formal or informal leaders of teams. What could they be bringing to the table? A (sad) exception is when access to meetings or information is gatekept, so then they're bringing that. Sometimes it's argued that PMs are good at seeing across things, but that has not been my experience. The problem with the each person is an expert in their own field is that in a lot of teams, the expert is frequently not better at their thing. The decision maker is not actually better at business or seeing across things or making decisions.