I really disagree with this. Obviously this is just anecdotal evidence, but I have several friends in dental and medical school who have community college credits. If you are an overall strong applicant (good DAT score, high GPA, and especially if you've made good grades in upper-level science classes at a 4-year university), I don't think CC credits automatically equal a rejection or even a negative mark on your application.
And I also disagree with the assumption that CC courses are automatically easier. I took the first half of Inorganic Chem. and Anatomy & Physiology at a CC, then took the second half of each at a 4-year university. I found both classes to be more intense at the CC, and thought that the professors graded harder and expected more from the students (for example, in A&P at CC, the tests involved a lot of short answers and essay questions, requiring an extensive understanding of physiology...A&P tests at the university were composed of fairly basic multiple-choice questions). I made A's in all four classes, but I worked harder for them at the CC. Obviously this isn't the case in every situation, but I trust that adcoms understand that all colleges and courses (CC or 4-year) are not equal.
I haven't applied yet, so take my input with a grain of salt, but I certainly don't think a strong candidate is automatically out of the running at most schools because of CC credits, unless those particular schools don't accept them. Perhaps if your GPA and DAT are average or low, CC credits might be a problem, but in that case you would have the same problem if all of the credits were from a 4-year university.
That's just my two cents. We'll see how it turns out for me next year.