Yeah it's a bit different because to use a gun you have to reveal the fact that you have a gun (whether through pulling the gun out of your pocket or by firing the gun, making a noise). Using a recording device is 100% passive.

If the question is "who should I hate more, people that I know could be recording me or people that could be recording me without me knowing", the answer is neither. In public, always assume you're being watched, always assume you're being recorded. In the US and the UK, you have no expectation of privacy in public places. I could be holding the world's largest and most obvious camera recording you walking down the street and you couldn't legally do anything about it. Just because that camera is pointing at you doesn't mean it's recording, either.

So why is Glass so different? The answer: because the real Glassholes want something to bitch about, and it's easy to hate on people who are different from you.