Don't feel bad. Their feelings were already hurt and you just happened to be in their way when they needed to vent. Shake it off.
Learning happens on the edge of chaos, in a space where our existing knowledge is challenged by new ideas and reshaped. Educating ourselves is a constant process of learning, unlearning and relearning. When our existing ideas are challenged and proven to be false, it's up to us to unlearn and relearn. Every day is a school day. We never stop learning and growing.
If you're looking around for another job, don't forget to read the fine details in the job description. What looks great on the surface might not be what you expected when you dig a little deeper.