What is wrong with being community-driven if you believe the community knows best?

I see two significant philosophical issues in this question:

(1) Value of the social form of existence; and

(2) Second-hander's approach versus independent thinking.

Ayn Rand discusses these issues in VOS, Chapter 1 (pp. 35-36 in the Signet paperback edition):

It is only on the basis of rational selfishness -- on the basis of justice -- that men can be fit to live together in a free, peaceful, prosperous, benevolent, rational society.

Can man derive any personal benefit from living in a human society? Yes -- if it is a human society. The two great values to be gained from social existence are: knowledge and trade.... every man gains an incalculable benefit from the knowledge discovered by others. The second great benefit is the division of labor: it enables a man to devote his effort to a particular field of work and to trade with others who specialize in other fields....

But these very benefits indicate, delimit and define what kind of men can be of value to one another and in what kind of society: only rational, productive, independent men in a rational, productive, free society.

The question expresses "being community-driven if you believe the community knows best," but the questioner doesn't mention how or why one would know or believe that. If all one does is surrender to whatever the "community" tells him is true and tells him to do, without any independent thought of his own, he won't actually be able to produce very much for the benefit of either the "community" or himself. Productiveness depends on rationality, i.e., independent rational judgment. Submerging one's mind in a "collective sea" of others' beliefs, feelings and ideas leaves one at the mercy of forces that one will not understand and will not know when or how to oppose if warranted. In general, trying to do whatever others do without much thought leaves one vulnerable to all sorts of errors and intentional perversions by others; it leaves one unable to know whose example is safe to follow and whose isn't and why. And safety is not to be found in the mere numbers of people who believe the same thing; shared beliefs, whether rational or not, are philosophically induced. Without independent thinking, one cannot identify the philosophical principles that underly common beliefs, and cannot judge whether those principles are valid. The idea of validity itself becomes displaced by "collective consensus" as the only test of veracity, and the philosophical roots of consensus become completely obscured and beyond the reach of all but a select few who choose to deal with philosphical fundamentals to shape the collective. The Fountainhead dramatizes the second-hander's approach and its debilitating consequences in vivid detail and variety. Refer also to the topics of "Society" and "Social System" in The Ayn Rand Lexicon.

In America today, in particular, it is becoming increasingly and urgently critical for independent thinkers everywhere to comprehend what the influence of bad philosophy has been doing to this country, and where it will ultimately lead if the trend is not reversed. Simply "following the crowd" will not save or protect anyone for long. Entire societies can perish; they are not automatically assured of enduring indefinitely without an explicitly identified, proper philosophical foundation.