Don't mistake me for an expert on the whole Taize thing. But my understanding is that meetings like you describe are generally seen as mission fields by exuberant Protestants. Specifically, evangelicals. What we're talking about is a spectrum of younger people approximately our age who are thoughtful and (somewhat) well-versed in evangelical talking points. They're not necessarily looking to start a debate in Taize. But they're also not looking to not start one either, in some instances.
Even so, ecumenism is a bit of a two-edged sword in this case. Yes, several of these evangelicals regard Taize as an opportunity to "convert" Catholics, it's true.
But the flipside to that, as you and I have experienced, is that Millennial Christians are uniquely drawn to Catholicism. I've heard stories from people more knowledgeable about this than me about Millennials entering Taize gatherings (for want of a better word) as seemingly committed evangelicals but coming out already halfway across the Tiber.
I'm not guaranteeing anything here. This is just stuff I've heard. Take it with as many grains of salt as you see fit.
