So out of curiosity I found the interview clip I think you're talking about, from an interview with Lou Mongello about a week ago. The clip itself is very uncontroversial - all Bruce says (this is my interpretation / summary, not verbatim) is that there are benefits to listening to young people and seeing things through fresh eyes. I don't think anybody debates that - it's good to stay up on current trends, it's easy to miss new opportunities if you've been somewhere for a long time and get used to "the way we've always done things", sometimes young people bring youthful enthusiasm and new ideas, etc.
Looking at a bit of YouTube commentary on that interview, I think the reason those comments were controversial is more the surrounding context of many seasoned Imagineers having recently been forced out or laid off, within the past five years. It's not so much that the idea of revere mentoring is bad - like many things, I think it's common sense with some slick packaging so that someone can sell the concept in a training seminar. Yes, listen to young people's ideas, that's a good thing. I think the issue is that some in the Disney-sphere feel it's not the time to bring it up - like they just lost much of their seasoned workforce, now that a few of them are back in consulting roles jumping to "But really let's listen to the recent college grads as well, let's not forget to do that!" is probably not the most salient message for this exact moment.
Interestingly, this does make me curious regarding where Bruce is coming from here. Like what is the backstory that makes him feel it's important to keep a focus on younger, newer Imagineers even as mentors are being brought back? Are we talking complaints on GS surveys? Budget concerns? Investor concerns about staying cool - wait, wait, sorry, I mean "sigma" - and relevant? That part is interesting.