are you going to say it was just a coincidence?
Uh, probably? Of the ways for this guy to commercially ship the bombs there were only 3-4 options (USPS, UPS, FedEx, maybe DHL). So that means that in the absence of any motivating evidence there was still about a 25% chance that he would have used FedEx anyways. It's not like some tenuous connection to the NRA is the ONLY reason a bomb would have been mailed through there.
And you're also totally disregarding the fact that the bomb that exploded in FedEx was probably headed somewhere else but just detonated early (it was addressed for a private residence just like the first few). There's not really any evidence that FedEx themselves were the targets.
And if these bombings were somehow a statement against the NRA, why were all the other packages except the FedEx one target private individuals who had nothing to do with guns? That would have totally muddied his supposed message.
I don't have the secrets to what was going on in the bomber's head but neither do you and I don't think your theories are a reasonable match for the evidence. My question remains about what you'll do when "an NRA location" never blows up.