Slight correction: 6mph or 10km/h is when the system calibrates itself and activates.I believe the owners manual states it will turn off after you hit 10 miles an hour.
However, the ABS light is similar to the check engine light of your car or bike. If it is on while you are riding then you have a malfunction. Lights come on in both on start up as a system check and visual that they do work.
I will clarify on 'while you are riding'. If you are out riding and it went off when you pulled from the drive way then came back on as you're going down the road you will need the system checked. Because if stays on for a minute when you first start getting the bike going does not mean 'you are riding'. If it stays on during a whole ride then you also have a malfunction.