Keeping and bearing is 2A protected activity. In states where it is not illegal, and if done in a way that is not unnecessarily alarming, I see no harm. Activism is 1A protected activity. Are we entertaining the idea that these two rights should never be exercised simultaneously?
If open carrying is done in a manner that is confrontational or especially threatening or with an angry demeanor, then I would agree that it hurts the cause. But to flatly assert that one should never practice 2A and 1A activity at the same time is perhaps over simplifying the matter.
As usual the devil is in the details. For any public activism, rather than 'ambushing' police with a situation that presents an unknown threat level, perhaps it would be wise and prudent to initiate advance cooperation with police to help assure them that safety would be maintained . . . not seeking permission, but seeking cooperation. Lowering rather than raising the anxiety level of citizens and those charged with protecting the public just seems to be common sense.
My 2 cents.