Is it true colleges won't read the whole essay?

It’s “poring,” not “pouring.” If that’s the opening line of your essay then, yes, AOs should stop reading. Similarly, the AO should move the application immediately into the reject pile if your essay starts out like any of those is these threads:
http://talk.collegeconfidential.com/parent-cafe/2108125-hypothetical-worst-first-line-for-an-application-essay.html#latest
http://talk.collegeconfidential.com/college-confidential-cafe/19427-worst-titles-for-college-essays-p1.html

Otherwise, don’t take the chance