You're absolutely right about David Biedny and his rep for bashing people about. He usually spent his time picking on the easy targets, like Horn or Bassett, but rarely asked the tough questions of someone like Vallee. But with Biedny, for all his flaws and his ego, you could usually at least count on a reasonably intelligent conversation, and it's worthwhile to remember that. I've had my issues with him since he quit, but I always enjoyed chatting with him when he was co-host and I was a guest.
Here are three problems, however, that are not particular to The Paracast (although they are relevant to the current version), and should apply to any show. In no particular order:
1. Sometimes, it's not the questions you ask that is the problem, but the fact that the guest was ever invited to be on the show in the first place. This is pretty rare, but it does happen. Exhibit A: Louis Jarvis.
2. Unless you have a well-known history of asking the hard questions even of your friends and relations, you probably shouldn't be hosting an episode that features close personal friends, particularly if you are involved with them in a business venture, or they have helped your career in some way. It's called a conflict of interest. I'll let people figure out which exhibit best fits this one for themselves.
3. Finally, when you do have a guest on, like a Ray Stanford, who isn't a complete nutter like Jarvis, but who has serious questions that need to be asked of him, you need to ask those questions, without fear, particularly when before the show you've solicited questions from forum members, and they've actually provided some. Also, if you fall under catgory #2, you should probably step aside and let someone else do the interview.
