As already stated, they have to respond to MWAG calls, so as long as you want to open carry you are going to have to deal with the police. You know this. Also as stated, if you want to change things and you want to stand at the front of the line of that change then you are choosing to accept the consequences of that.... and in that case it means dealing with police officers.
Perhaps if you could arrange a civil sit-down with your local Police Chief or perhaps you could write a civil letter. You catch more flies with honey, you know.
I am all for open carry and have done so myself from time to time, but I do think it has its time and its place. You know exactly what you can do if you want a break from the "harassment".. you conceal. But if you choose to stick your hand in the bees nest don't be surprised when you get stung a time or two. Eventually things may change and OC might be more socially acceptable.. until that time you know exactly what you have to live with and what you can do to change their response. Unless you can find some legitimate legal action (provided you can find a good lawyer and build a solid case) or find some way to change things from within the department, you are pretty much going to get what you've been getting.