That's because the developer's OS support is outside of Vivox's prerogative. They tried to change the developer's plans because they couldn't fit in them. If their reply had been something along the lines of "We don't support Linux and can't help you with that" I'm certain most people would be fine with it.

Their original reply makes me think of a hotel that can't accommodate a family of four so they suggest you leave the kids to the grandparents and go on vacation alone. It solves their problem, not yours.