As for the issue of "would-be enthusiastic employees becoming disengaged because their ideas are not given a fair-hearing", I do agree. This also affects communities, and even interpersonal relationships. There's hardly a better way to destroy someone's willingness to help if you keep hurting them at their most vulnerable period - when they're full of enthusiasm, and trying to contribute their best.

I unfortunately know it from personal experience, from way before I entered the job market. I've always been full of enthusiasm for stuff, but after few unfortunate episodes in my past, I find it hard to share that enthusiasm with people - especially those close to me. I like to think I'm making progress in fixing the damage, but the process is slow.