Is this for real in Pennsylvania?

[0rganism]

19. might be worth finding out which company leases that billboard

free speech in public space is one thing, but this might have other applicable regulations.

if it's a 3rd party, not Mr. Douchebag Placek, they may have some rules of their own which limit the kinds of content renters can display on their property. it's quite possible the owning company knows nothing of this, or expects very few people to notice and object. if they see a growing awareness that their brand is tied to some sick racist bullshit, they might be persuaded to take it down.

if the asshole owns the billboard outright as well as the property on which it stands, then there's little recourse. on the other hand, if one had, say, a paintball gun and needed target practice, there might be a more challenging, but possibly more rewarding, path of mitigation.