I don't know anything about the CFTC in particular but I'm familiar with the general idea of lobbying and the role it plays in a representative government.
Elected officials have to interface with basically every industry in the country. How is any specific representative in a legislature going to have the knowledge required to vote on a banking act? Or a bill pertaining to power plants? Or cryptocurrencies?
Does it make sense to allow representatives from various industries access to members of the legislative branches of government? How else could Cynthia Lummis or Kirsten Gillibrand make an informed decision when writing federal laws related to cryptocurrencies? Should there be federal laws related to cryptocurrencies? Should legislatures have a government regulatory agency that enforces federal laws? Who is going to write those laws? Should there be a federal agency like the SEC, but specifically for cryptocurrency? Is that the CFTC? Who should make up the CFTC? Who should make up the SEC? Are the people who are qualified to work for industry more or less qualified to work in the agency that regulates the industry? Who is best qualified to lobby for the industry? For the people who work for the regulatory agencies or lobby for industry, are they owners or laborers in the regulated industry? What if everyone at least wrote their name down on a big public list and said who they worked for and published when they met and who from which government position they met with?
Are there easy answers to these questions? How the hell has any of this ever worked?