Think vs. feel?
While I can understand why you might see the terms as being oxymoronic, I consider them to be separate but related in the development of a greater understanding or awareness. Reflective writing often asks people to consider objectively their experiences or feelings and then to communicate their thoughts to their audience. In that effort, thoughtful evaluation of feelings, such as "why did that response make me angry?" or "how could I adapt my emotional response in that situation?" is often key to developing a new understanding. As a point of interest, the MBTI personality type inventory separates thinking and feeling as two approaches to decision-making; for more information, please see "Thinking or Feeling" from the Myers & Briggs Foundation.