I view it as a First Amendment issue. We can call out "privileges" that lobbyist groups have that ordinary citizens don't (which as far as I know are not grante

I view it as a First Amendment issue. We can call out "privileges" that lobbyist groups have that ordinary citizens don't (which as far as I know are not granted by law, they just have to do with the size and influence of the groups). But a lobbyist is just a person or group that voices an opinion to law makers. In theory, literally any individual person can be a "lobbyist" and preventing the practice would prevent people from talking about issues to lawmakers. Which would be the exact opposite of what we would want in a democratic system.