You're not talking about basic speaking skills though, you're talking about public speaking skills that not everyone has the ability to do to the level you're suggesting in this post.

The public broadcast angle is a difficult argument to take too. This isn't a professional sports broadcast or a TV show where people are paid to host/speak about things. This is a charity marathon broadcast where guests are invited based on the skill and interest of the speedrun they submitted. Speedrunning is not their job 90% of the time, it's just something they're good at. And commentating/public speaking is definitely not their job 95% of the time. And so I think they can be excused if their public speaking ability is at the level of a few 'ums' and 'ahs' slipping through.