While labeling people into groups can add to this, it may not be possible or desirable to refrain from this entirely. You would want to distinguish between criminals and friends, for example. Likewise, you would probably not want to associate with people whose interests and beliefs are so against yours that the relationship is strained or unrewarding. Loss of respect for others often comes from not being taught to respect yourself. This means learning to sacrifice yourself for others, without regard to what you want to do with your life.
Guilt is a terribly crippling thing, and is often at the root of religious and politicial doctrines.
That is, you should feel guilty if you are not sacrificing your needs to those of others to the extent that some traditional collective wisdom dictates. I submit that self respect must come from an honest, natural willingness to explore and express your own selfishness, preferably in ways that does not hurt others. A link to that section is provided at the end of this document. Respect yourself first, shedding the guilt others heap on you for not sacrificing your interests, and then you are ready to respect others. Now, back to communication.