my take away from this is that this is not a problem caused by the FOSS community as such, the FOSS conferences are just mirroring other problems. (although the numbers are probably not statistically valid, this would indicate that FOSS is slightly better than the non FOSS events, 30% bad FOSS vs 50% bad other, not that any of these are good numbers)
the way the article is written (and the way people are understanding it, based on some of the comments here), it sounds as if this is a problem caused by the FOSS community.
I am surprised that your experiences have been that bad, I get to a couple major events a year and have never witnessed anything along the lines of the 'bad enough to contact security' types of things. I have heard comments that could make people uncomfortable (and heard some that made me uncomfortable, including during some keynotes, after which I have complained in writing about the lack of taste of the presenter, feedback is good)