Citizens can absolutely do that.
Corporations might be "people" but they aren't citizens. Especially if they participate in shenanigans designed to "minimize" their tax exposure that involve shell corporations in other countries.
it would be a very different and interesting world if individuals lost their right of free speach if they organize as a group
As the bumper sticker/fridge magnet says, "I'll believe corporations are people when Texas executes one of them".