I am very much a message board nerd; it has never been my intent in invoking that term to set myself apart from other people. You can verify that for yourself with the search bar at the bottom of the page: I'm usually pretty careful to include the words "like us". I wasn't this time, but now you know, and we don't need to litigate that point anymore.
Your latter point is pure relativism. What can't you say that about? People make important business connections by going to bars together, by asking their friends for favors, by selecting cofounders, by playing in the same video game leagues.
The argument about the Hollywood blacklist would be biting if I hadn't foreclosed on it in the comment you responded to without reading very carefully. Perhaps you thought that point was crafty or subtle, but it is in fact banal, lumbering, noisome; you can see it coming on the horizon from the first words typed on a thread like this. You might as well invoke Nazism.
My argument is simple, and you'll need to address it head on. The people suggesting that excluding any speaker ever is some kind of Pandora's Box that opens every event up to trolling and zealotry are making two untenable arguments:
* That there is a set of principles about exclusion OR inclusion that is somehow immune to gaming and manipulation by bad faith participants. No, any set of principles you conjure will be gamed if you don't use judgement.
* That there even exists some simple set of rules we can all follow, something that fits in 80 columns to match our source code style guide, that will resolve all these problems. No, these problems are complicated.
You want this problem to be so simple that you can beat people over the head with the obvious right answer. It's not simple. It's complicated, multi-segmented, floppy, unwieldy. You swing it through the air at people's heads, but it curls up on itself as you do, and the only thing that hits your opponents argument is a bit more air.