A few reasons it's a major part of the decision:
Firstly the coders really don't like doing support in hostile environments. It wears them down and if they have the choice of not walking into that environment they'll generally choose not to. It's harder for me to convince the guys bringing their work to xF is a good idea if they think they're going to have to deal with... difficult people when they do.
Secondly the market share of xF is still really small - its growing but compared to vB or IPB it's still tiny. To get xF to be profitable would basically mean being able to have a receptive market to the pricing structures required to maintain profitability. As the market exists just now there are lots of cheap mods and cheap/free branding free initiatives. That's fine for someone doing it as a hobby, but the truth is those people and their work won't be around long, because they're simply not making enough money to make this a full time job. What that means is for profitability to be possible the market has to be "conditioned" to realise that a certain price level is required to get professional work that will be supported and updated long term without people vanishing into the night.
That conditioning is really hard to do when there is an extremely vocal minority trying to push resistance to it. Those guys don't care if they don't get good coders here long term making enough money to live on - they just want stuff as cheap as possible for them, with the copyright layout THEY want and they'll do or say whatever they have to in order to keep the market prices at a low level for THEM, regardless of the damage long-term.
Thirdly, xenForo will be unprofitable for us in the short term for sure, probably in the medium term and very possibly in the long term. The truth is that dealing with difficult people saps motivation and takes it out of you - no matter how used to it you are. Getting up every day and releasing things to people that they will use on their sites, often for free, then come to you and try to make your life difficult is hard to do when you know you're LOSING money on it. Doing it for people who are appreciative, friendly and understanding is a LOT easier.
The truth is that we don't have to deal with any of that stuff in the vB community any more. It's very VERY rare for us to get a negative comment or post either on our site of on vbulletin.org anymore. We've had more on xenforo.com in the last year than we have on our site and vbulletin.org combined. That's despite vBulletin having a community dozens of times larger than xenForo's. That's just crazy - pure numbers should mean there are more people on vBulletin giving us crap, yet not only are there more on xF as a percentage, but there are more as a whole number as well.
TL;DR When you're trying to grow a market, vocal resistance makes it several times more difficult than it has to be. When there's no guarantee of profitability in that market it becomes a serious consideration.
We have a reasonable understanding of the framework - we were here on Day One, with a few licenses purchased to support KAM in the face of the lawsuit.
