They should make the bridge program (well, at least the equal payment part) standard for all Shutterstock contributors. It's a shame that they think paying a lower rate is ok.
But they obviously decided that the bridge is only for some selected contributors. That tells me that they don't really value the content of the non-bridge contributors.
If that's their opinion, than why upload any more? I stopped the moment they announced those rates. Once they agree to pay the same rates as on Shutterstock, I will upload again.