Heaven forbid! THANK GOODNESS there is NOT a 'Like / Dislike' button!
A representative group of people, with opinions clustered around the centre, and only a few out-lying extremes, would be subject, (just as on FB) to recruitment into two clusters polarised at the extremes.
We get enough divisive posts as is, without magnifying differences by the FB effect whereby the strongly approved of or disapproved of opinion attracts responses which drown out any moderate voice.
Even Sir Tim Berners Lee has had to move from his advocacy of internet freedom, to recognise that it is in need of some protection from this malevolence.