Just playing devil's advocate:
Isn't such behavior a reflection of how things
really are? We do and say controversial things over here, which many people don't like. If we don't allow them to express their views, we end up sheltering ourselves and this place from dissenting positions. We may become less aware of them (both positions and their authors), which may result in us neglecting one of the most important duties of this forum, i.e. education.
Beyond the above, usually discussions over here are fantastic to read, sometimes they go offtopic and I see every now and then people become less than excellent to each other. Right now the only solution is to call the authorities (Report feature → mods roll in with the big guns). I think a "dislike" feature would provide an effective tool for the community to self-regulate. And make mods' lives easier.
I believe it's possible to implement such feature and prevent / limit abuse. Here's a few ideas:
1. Don't call it "Dislike". That implies a quick, emotional reaction. I think "Helpful" / "Unhelpful" would be worth a try. (Ha,
@Sokel beat me to it)
2. Implement a time limit between uses, let's say one reaction per 10 seconds. It's more than enough to be a deterrent for the emotional, who are usually also impatient.
3. Implement a confirmation step, especially for the "unhelpful" function. Test it vs #2 above, both features most likely would be too annoying.
4. Implement a reporting system, e.g. mods should be notified if one particular user "disliked" many posts in a short amount of time, or "disliked" many posts by one particular user.
5. To
@Soria Moria 's point -- it would be helpful to also have a "Funny" reaction too. There is a lot between helpful and unhelpful.
