It depends upon how you converse with them.
If you talk down to them with what they consider to be a superior attitude, you will most likely get the responses you describe. If you talk to them in an engaging and friendly manner, even if they don't understand, they might express interest, or at the very least, politely go "uh-huh," and then change the subject...
Effective communication and interaction is a skill, and unfortunately not one easily mastered when dealing with people less intelligent than you. So, you either learn how to "talk stupid" better, or you learn to not say much of anything, or you speak your mind, and don't let it bother you when the stupids give you a stupid reaction. When you do come across those with more attuned gray matter between their ears, they'll give you the feedback to let you know by becoming animated and listening to what you say, and actually discussing subjects with you.
It took me years to learn the first one, and I still suck at the second. I'm pretty firmly entrenched in the third, and only resort to "stupid speak," if it is important, and then I try to use REALLY plain words, and speak as clearly as I can.
Life's too short to waste it on people with no real grasp of the world around them.