Defensive lobbying, which is what we can call lobbying to fight the lobbying that has anti-liberty or hostile special-interest intent, is clearly a good thing. One would hope that a representative could figure out that if a paid lobbyist is necessary, then the concepts being presented by that lobbyist are complex enough that a voter of average intelligence could not understand them, further inferring that the concepts themselves are contrary to ordinary principles of liberty because those principles and those of the free market are simple.

Politicians get elected by being liked by many voters and therefore tend to be susceptible to peer pressure. (President Trump is a dramatic exception.) With susceptibility to peer pressure comes a tendency to jump to a socially accepted conclusion when presented with an avalanche of complex commentary, allowing an unscrupulous lobbyist to overpower rational thought in a representative. Banning paid lobbyists would be a free-speech violation, and I don't approve that reaction; but if only the unpaid sincere directly motivated citizens could try to persuade representatives of anything, then the likelihood of having a representative swayed by a professional brainwasher would be greatly reduced.

Voters nowadays tend to vote based on charm and personal compatibility and not on economically defensible platforms and soundness of intellect. The problem will exist as long as voters are lazy.