At my last company, we paid for a Zeus ZXTM license (which was an excellent product and very expensive for our little startup), and they didn't approach the level of arrogance here. The varnish guy is kind of opinionated, but he's got the chops to back it up, and you can, y'know, look at the source.
An obvious benefit of open source is also that if I take a large risk of running my business on your oddball web server and you get hit by a bus, I'm pretty much hosed. I'd rather buy 4 additional servers and run nginx than take that risk. Or, y'know, use a CDN.
Whatever, if the developers really are THAT much more skilled and their product is so far and away better than every other solution out there, then they should really hire someone who knows how to do marketing and PR properly, because they're not doing themselves any favors.