Lobbying is just another word for bribery. This used to be illegal and I'm not sure how or why it became legal in the first place.
Your right to bring your concerns to your elected representatives and executives is preserved, very carefully and deliberately, in the constitution. Likewise is your right to assemble in a group to get things done.
So, you think that a visit to your congressional representative's office to explain your position on (pick a topic ... net neutrality? gun control? immigration? whatever) should be illegal? Why do you think that? "Lobbying" is the act (historically) of waiting in the lobby of a building to for a moment to bend the ear of a passing legislator on his or her way between other engagements. Hence the term. You're thinking that should be illegal?
Or are you just not happy when you and ten of your friends who share a common interest designate one of you to make the trip to that same office to speak on behalf of the other nine of you, as a group? Is that the part you think should be illegal? How about when you and your ten friends realize that there's actually a million of you that have a common interest, and you decide to pool some resources and hire someone who lives and works in the state or federal capital, and who knows who and where everything is and how it all works, to explain your collective position and priorities to that same congressman? Is that the part that should be illegal? Why? Which part is the illegal part - where a million of you act in concert, or where you finally realize that having a professional pull your agenda together into a coherent, easily conveyed whole means that you hire someone for that role? Please be specific about which thing you'd make illegal:
1) Gathering in groups?
2) Pooling resources?
3) Hiring someone?
4) Talking to congressional representatives or regulators?
At which point is someone bribing somebody else? Do you mean that the congress person is actually taking cash under the table? Do you have evidence of that happening, and it not resulting in prosecution? If you do, why are you keeping it from the FEC and the other agencies that investigate such crimes?
Or is it that you just don't like the fact that people who run businesses decide to take some of their money and hire professionals to reduce the overall noise level and represent their interests in a more focused way? Do you not like that because you can't be bothered to identify a suitably large group of people who share your own interests, and who do exactly the same thing? Millions of other people do - do you think that the NAACP, or the AARP, or the Sierra Club, or the NRA, or labor unions or other groups should be barred from taking their concerns to their elected representatives in a unified way, instead of expecting all of their thousands or millions of members to descend on the same congressional office individually, all day every day, to say the same things?