I suggest at the outset taking everything you read on EphBlog with a massive grain of salt. Its creator and main contributor, and most of the commentators who remain, are far-right critics of the college in particular and academia in general. They have an agenda that just about everything offered on the blog is filtered through, and that agenda includes, in particular, hostility to racial diversity, environmentalism, and liberalism more generally. The comment sections, in particular, have been taken over by some extremely unhinged right-wingers, in some cases outright bigots, who have scared more moderate contributors away. In short, the blog is in no way broadly representative of Williams’ students or alumni, and instead represents only a tiny sliver of the college community.
All that being said, Ephblog occasionally offers some useful – and at times accurate – insights into the college’s pratices. Alas, it is impossible to untangle that from the deceptive or outright false rants about the college that proliferate on the site, as well.
From everything I’ve heard and read, this particular post is just not accurate. Now, of course your odds are MUCH better if you have elite grades and academics. But plenty of applicants with near-perfect scores and grades, but with weak applications otherwise, are rejected, and there are plenty (although of course the odds are long) with below-average grades and/or test scores who get admitted even without being an underrepresented minority, a legacy, or a high-priority athletic recruit. You have to have a really compelling story to present under those circumstances, but it can’t hurt to try and some do succeed, and part of that success is certainly grounded in EC leadership / excellence (e.g., a very talented artist / musician).
In all events, EC’s and other personal characteristics, while not the most important factor for admissibility, definitely matter for Williams. (They certainly did for me, and for many applicants I’ve known over the years). But in the end, if your academics aren’t at least roughly within range, they aren’t going to prove dispositive except in extraordinarily rare cases.