We are suppose to be a gated community but there are only 13 houses. We are in an mid to upper level, but am with you, I cannot see any reason for locking our gates.
It would be a pain since we live on a one way street. I certainly approach the other neighbors and see if the majority will rule. But, the neighbors probably have no idea of the unlimited expense it can cause. Not counting the initial cost there is always something that needs to be done and the HOA dues are always high, Maybe they want that to keep others from moving in. It sounds like they have not really thought this thing through.
Once they get the area gated, then they will want new bi-laws and conventants and they will be telling you what kind of wreath (if any) can be hung on your door. It really does mushroom and get out of hand. Then there are special assessments for items that were not planned for. Extra insurance and so much more that apparently aware of. Maybe you will want to make a list of some of the potential problems and let each person see what could happen.
You may want to take the plans to the local or city zoning board to see if can be done. In may cases you cannot. Check your bi-laws and covenants too they may prohibit it. But, do not give up, have them sign a petition against it it you can.
If they cannot prove a reason for it, I doubt the city will approve it.