I wouldn't give much weight to those congratulations. When I went vegetarian a lot of people did the same. Most new acquaintances that discover my vegetarianism respond very positively, specially left-leaning people. Although I try not to preach, I'm too often the only one that orders a salad. But they always follow it with "I see that it's wrong, but I could never stop eating burgers/cheese/jamón". I'm not even sure they truly think it's wrong, but feel a need to say it.
It's one of those things that many people associate with positive traits or stories. We've all seen the inspiring posts or youtube videos of the people who refuse to use a car because of pollution, or stop eating meat because of animal suffering, or will never use a device that runs proprietary software...
We seem to like these stories, and sometimes even admire the commitment, while having no intention of doing anything like. We feel good for congratulating them of tweeting our support.
(For example, many here admire Richard Stallman's commitment and honesty, and agree with a lot of what he says, but read him froma Mac. We are never going to switch to an old libreboot-able PC with gNewSense, but we sympathize with his cause.)
Many people love Facebook, and many others hate it but can't be weaned off it. We won't get very far by abandoning Facebook and prompting others to do the same. We'll a alternative, and/or very strong positive and negative reinforcement to do so.
> The difference is these few days blew off the periphery of uncertain users. It won't hurt them now, but in the long run - it may be like tobacco.
Your comparison with tobacco is very apt. People stopped smoking when a) leaving it was applauded, and b) people still smoking were starting to be seen with some contempt. It took a long time to build those up though. We are very far away from that with Facebook, and even if us leaving is the beginning, I don't think we want to wait 10 or 15 years. Tobacco damaged lungs, Facebook damage could be much more insidious.