Your theological bias will determine your interpretation. My theological bias disagrees with the statement above. It is natural to talk about what we are excited about, whether that be model airplanes, gardening or the stock market. The worst thing we can do is to make people feel guilty about not witnessing. In Christianity, guilt is the problem, not the solution.
Grace is the solution.
When people are sufficiently excited about grace, they will talk about it, in the same way that they talk about gardening if they are excited about that. Our job is to teach with zeal and enthusiasm and trust people will get excited about God. When they do, talking about it will be the leased of our problems. The key thing is to start with getting people filled with the Spirit. The last thing we want is for people who are not filled with the Spirit running around telling people about it.