The problem is that in order for people who do a public facing job where their personal reputation and popularity affects the company's fortunes to have free speech without consequences everyone else would have to be forced to support the company no matter what. Boycotts could be made illegal, but how would you stop people uninstalling Firefox after his appointment?
Like it or not personalities matter when it comes to CEOs. Remember all the personal hate for Bill Gates and the way he acted at Microsoft? All the love/hate for Steve Jobs, who arguably was responsible for much of Apple's success due to his strong personality, his outspoken views and "reality distortion field". There have been endless cases where people paid to advertise a product have been dropped over things they did or said, because their actions tarnish the advertiser too. At least in the case of a CEO they have some involvement in the thing being tarnished and aren't just a pretty face.
I agree that leaks are worrying, but in this case I'd argue that donations to political campaigns should be public. If someone without money to spare wants to endorse or promote a cause they have to speak, revealing their position. Just because you can afford to give up $1000 shouldn't excuse you from that responsibility. Yes, you are free to say what you want, but you are never free from the consequences.