Because it sticks out like a sore thumb, and has trademark problems irrespective of its reuse. And you know, everyone deals with naming things, so we can all relate and pull from our own experiences.
Again, the number of people who this impacts is so small that it's hardly significant. Sure, here on HN I'm sure it seems that everyone is confused, but we're hardly a representative sample here.
> has trademark problems
Honestly I don't buy this. When you trademark something, you do so in a very specific manner, and I think Screen's market is specific enough as to defend a trademark in the screen sharing/collaboration segment _should they even choose to trademark the name_, which they can easily choose not to do.