I'm of the opinion that most on MN are not just sheep, so the 'baa baa' comment is rather negative of others, but that's perhaps because you are equating the ability to 'like' (and I suggest also being able to 'dislike' for balance) as being only for those who are thick and/or juvenile. Well, maybe it doesn't suit your views, but there are many who would like the option, and until MNHQ has commented in the negative, it seems they are willing to look at this.
While I've seen comments suggesting a 'like' button could replace discussion, I suspect there are sufficient numbers of people who have opinions and will continue to write them when they feel the need (and have the time).
People have lurked rather than posted for weeks and months (you must have seen the "this is the first time I've posted, but been on MN x years") and if being able to just agree (or disagree) with a specific post draws those people on to the next stage, I see it as a benefit.
lawnimp - MNHQ has been making changes every few weeks for as long as I can remember, whether it is to change headings, add facilities (like bookmarks, colour choices) or change links and searching (well, they've broken that for a bit!), along with changes for users of mobile phones.
It is unrealistic to assume you will have the same facilities this time next year as you have today, and much of the time, people on MN are the ones suggesting changes... Personally I don't use Facebook or Twitter, so the links MNHQ has added are of little value to me, but clearly they felt it made life easier for users, and this is just another suggestion.
This has come up more than once with different groups expressing interest at different times, so it's hardly a recent suggestion for the sake of it.
As you can see, the thread is some months old, and sadly MNHQ has not yet come back to this, so with a bit of luck the extra posts will draw this thread to their attention once again!