People generally want to do their best, including the project managers you refer to. Project managers with less tech expertise will often find themselves frustrated that they can't get what they want. On average, I would expect them to participate enthusiastically because this will help them be more effective.

At different companies, there will be different pain points: salespeople who overpromise, pixel-perfectionist designers, etc.

Regardless, having people speak the tech team's language will tend to benefit the tech team, so it behooves us to take a positive attitude when people are willing to engage.