Science is repeatable, not repeated. It's not true that one experimental result is meaningless but two are gospel. The first has a probability of being a fluke, and the second reduces that probability, that's all.
Indeed, this is true as well. Science isn't the right place to look for absolute certainty. But still, there are some obvious things you can do to increase confidence in a result, and one of those is to get other people to try to reproduce those results.
