"When the public cannot understand a picture or a poem, they conclude that it is a bad picture or a bad poem. When they cannot understand the theory of relativity they conclude (rightly) that their education has been insufficient."
There is always the possibility, when one views a picture or reads a poem, that it is actually crap. With science, findings are published in peer reviewed journals and include methods, data and calculations to justify the conclusions. You can review their logic or even repeat their experiments. It makes sense to trust science more than art.
This is not to say that Russell doesn't have a point. It is just that great science should (if things are working correctly) always be recognized. The process holds findings up to objective scrutiny and so it will be accepted or rejected quickly. Great art may not end up being appreciated in its time and this is due to the fundamentally subjective nature of art.