There was no reason to be worried when it was active, much less a reason once it's dismantled. You personally could take a tour of the facility if you wanted to during its open house days, and many reporters, scientists, and foreign dignitaries have done so by request throughout the rest of the year. Its findings on ionospheric research are routinely published in public scientific journals.
All the conspiracy nonsense that has arisen from this facility has been bizarre. I can at least sort of understand the people who get paranoid over Area 51 and similar facilities, because they're totally closed off to the public and those without clearance, but HAARP is very accessible to both visitors and people who want to learn about it online, and its purpose is fairly innocuous and limited.
Besides, people should be thankful that HAARP has perfected the features of
Mikkos Cassadine's plot to freeze the world and
COBRA's Weather Dominator. It might be our last best hope at reversing the worst effects of Global Warming.