Do people sharedrop on Bitcoin because everyone uses POW? I don't think so....
You already forgot the existing social contract my friend!
That social contract is only if they wanted help from our community I believe. The code was open source and free to use. They have no obligation towards us, however, we, as a (much bigger) community won't care about helping them at all. But since they don't seem to mind, I don't see where is the problem. The more projects use DPOS the better because ultimately we are the ones who will get recognition