I don't think you're making it up, it sounds like you had a bad experience, and someone from Motorola biz-dev/m&a was being a jerk, but without knowing how the interaction went, it's not really my place to pass judgement. In a company of 88,000 employees, there's a non-zero probability of getting a bad interviewer.
I'm sorry to hear you had that experience. Where I part company is the added interpretation. If I was in your situation, and had a negative experience, I'm pretty sure I'd be angry, and feel wronged, and feel 'used', it's only natural.
I mean, Dropbox tried to sell themselves to Apple and Steve Jobs didn't like the price, he went on to say 'you dont have product, you have a feature', actually worse than that:
"And so he started trolling us a little bit, saying we're a feature, not a product, and telling us a bunch of things like that we don't control an operating system so we're going to be disadvantaged, we're going to have to figure out distribution deals, which are risky, and sort of a bunch of business-plan critiques. But then he was like, 'Alright, well I guess we're gonna have to go kill you, basically.' Maybe not in those words, but pretty close."
But do I believe Apple "stole" Dropbox? nah, cloud based backups, sync, etc are pretty straightforward, and although there is innovation at the UI and syncing protocol layer, iCloud is not really a Dropbox clone.
BTW, I encourage you to continue to try and innovate around your idea. There may be a use case beyond 'speakers', like emergency alerts, security, think "California earthquake imminent in 10 seconds!". There could also be a use case for synchronized sound based gaming at parties. There's loads more to do, and having had some bad experiences shouldn't discourage you, it kind of comes with the territory of presenting ideas and startups, you really get shit on a lot.