My dad was 82nd. I didn't see the incident he was talking about (could have been an isolated occurrence) but I have seen similar incidents in the past in other areas, especially in the 70s. I saw small demonstrations outside some of the bases here in the DC metro area during the Gulf wars by small fringe groups who were yelling insults and carrying insulting signs.
Besides, just because some area is not a "bastion of liberalism" as you so eloquently put it doesn't negate the existence of radical liberal elements in the vicinity. Figured that would be obvious.
First, this is not the 1970s.
Well, duh.
Secondly, there is always a degree of bad-will between the base community and the local community. If this incident did happen, it doesn't automatically make it a political statement.
Again, well duh.
Third, protesting is one thing. Destruction of property is quite another.
Double again, well duh.
Fourth, since all bases were locked down after 9-11 and the gates were manned, I am curious as to how a vandal with a can of paint could carry out such a covert operation.
I don't remember him stating it was "on base". Maybe just outside the gate.
Incidents like this (and the veterans getting spit on) rise to the level of urban legend simply because they can't be independently corroborated. The truth could be exactly as the OP claims, total bullshit, or anywhere in between.
Third well duh.