I don't see how there could be an argument for protected speech here. The constitution protects your ability to petition the government, not the government's ability to petition you.
I don’t know if the claim is true, but if it is, it’s likely an intentional loophole because the people writing the laws would want to exempt themselves.
Yes this is what happened. There are specific carve outs for various uses that don’t fall under the legal definition of “spam.” Of course political advertising is one of them.
Just like for the longest time it wasn’t insider trading if you were a politician.