Why is everyone blaming the lobbyists?

If someone offers you a lot of money to do something unethical and you accept it, how is it the fault of the other person? You're the one doing something unethical.

Lobbyists are just doing their job. If people don't like politicians who are swayed by lobbyists, vote them out of office and elect someone who won't accept lobbyist money. That's one of the benefits of a democratic republic.