Not everyone particularly appreciates a "take" that's different from his own.
Since I'm really not "socially clueless" at all, that's one thing that makes me refrain from "trying to contribute" to a lot of discussions by adding my own comment (or "two-cents' worth).
When people are on a social site like this one, who remain silent (in the name of not wanting his motives for enthusiast "contributions in the name of 'sharing-a-take-is-genuine-participation") say nothing, it's not really a big deal.
In offline and more personal relationships, however, being someone who always wants/needs others to agree with what one says can set up for, or place a person at higher risk for, some pretty unhealthy situations in personal relationships. It doesn't do much for others who have learned that remaining silent and/or saying only what someone else wants to hear either.
I don't know... It's just unfortunate that the idea of people's having different takes on different matters is so mistaken for being "unfriendly" when - in reality and in one way or another - it's really intended to be just the opposite of "unfriendly".